Using Modify Memories against a party

[Galithar]

I have an idea I would like to use against my players. I have a bad guy that would want to manipulate the players with a modify memory spell. Now, I don't want the players to have any knowledge of the original event, and the modification would be changing WHO was involved in an event, not the actual outcome.

So my idea is this, I would have them roll the save at the beginning of a session (before the events that would be modified) Now this would be a high level enemy with a high save DC manipulating the party while they are at a low level. The chances of a successful save are low, but I would abide by a success (The person(s) that saved would privately be given a different accounting of the events after the full resolution).

This is slightly railroady, because I am not giving them the possibility of avoiding the casting of the spell. I feel this is well within the realms of possibility as the caster also has access to scrying and other magics to make sure this happens.

My question is this, as a player when you inevitably find out your memories were modified would you find how I did this cool? Or annoying? Do you have a suggestion to do this better? (The Modify Memory spell is going to come from a HomeBrew artifact that gives the spell an AoE that the party may gain access to, but most likely would choose to destroy as it's sentient and evil as hell)

[Eldariel]

Kinda cool, but it would be difficult to keep things straight and figure out what part was altered and so on. That's kinda as intended but since players don't live PCs' lives, it'd be much worse in a way since it's difficult enough to maintain the self-separation from the PC at clear times and then having to do in-depth reorganisation of the PC's memories and knowledge is another thing entirely. It would certainly be interesting to try and I'd be thrilled about it happening: it would be really cool in the story. But it would be a lot to the player especially without the campaign journal being written down (which would make it easy to cross-reference the modified and the real events when they finally do come across the real history).

[Galithar]

Kinda cool, but it would be difficult to keep things straight and figure out what part was altered and so on. That's kinda as intended but since players don't live PCs' lives, it'd be much worse in a way since it's difficult enough to maintain the self-separation from the PC at clear times and then having to do in-depth reorganisation of the PC's memories and knowledge is another thing entirely. It would certainly be interesting to try and I'd be thrilled about it happening: it would be really cool in the story. But it would be a lot to the player especially without the campaign journal being written down (which would make it easy to cross-reference the modified and the real events when they finally do come across the real history).

The event in question is going to be a fight. The modification will simply be masking the identities of their enemies in order to throw the PCs off the track of the true culprit. Since the fight will likely take less than a minute it's well within the ten minute limitation of the spell. It also means that when they find out it's simply going to be a case of "You had a sudden realization that the people you fought for possession of the McGuffin were actually members of organization X, not organization Y!!" Where organization X was a supposed ally and organization Y will be the Patsy they THOUGHT they were working against, but in reality would either be unrelated or actually on their side.

[Parra]

if it were me as the DM? I would just carpet say the MM affected all of them. Then I would sit on that information until a restoration spell was used, maybe even engineer a situation were restoration was needed. Then let the restored PC have the 'true version' of the events.

sure thats maybe a little railroady, but it'd work out if you played it right.

[Galithar]

if it were me as the DM? I would just carpet say the MM affected all of them. Then I would sit on that information until a restoration spell was used, maybe even engineer a situation were restoration was needed. Then let the restored PC have the 'true version' of the events.

sure thats maybe a little railroady, but it'd work out if you played it right.

That's basically what I'm doing. Just that I'm allowing the saving throw to be made as normal. Though they will have no idea when or what caused the save. I'm going to have them roll it at the start of a session and reveal the truth to anyone that passes. It will be highly unlikely anyone passes as the check will be made at level 3.or 4 and the save DC is going to be a high. Depending on the final stats of the sentient item used by the BBEG which aren't set in stone but will be between 22 and 24 (Int 26-30 with a proficiency of +6). The artifact has the mind of an extremely powerful Mind Flayer Lich that was bound in a time long past. Only whispered about in old legends. It is the "true" BBEG in this case as it is exerting a lot of influence over the wielder, though not direct control.

[Eldariel]

The event in question is going to be a fight. The modification will simply be masking the identities of their enemies in order to throw the PCs off the track of the true culprit. Since the fight will likely take less than a minute it's well within the ten minute limitation of the spell. It also means that when they find out it's simply going to be a case of "You had a sudden realization that the people you fought for possession of the McGuffin were actually members of organization X, not organization Y!!" Where organization X was a supposed ally and organization Y will be the Patsy they THOUGHT they were working against, but in reality would either be unrelated or actually on their side.

In that case, yeah, cool, especially if given the check. I hate narrative "It just happens" but when it's "a powerful sentience uses magic on you and you fail to shake it off", that's much more palatable. Especially if you remind them later that they did indeed all fail the save (that was theoretically doable; probably Wisdom so a Cleric/Druid could be looking at up to +5 giving them something of a ~10-20% chance of saving, and a race with Magic Resistance/Enchantment resistance could do the check at advantage for 19-36% - or someone could have Portent to be potentially able to use their daily 20 or whatever on it).

[Zhorn]

I'd suggest having a read of some games run using a False Hydra to mine for ideas.

The general pattern for those types of altered memory games usually has the party show up to a location with some message (letter or otherwise) asking for aid, but when they get there no one knows why they were summoned, including the NPC that asked for them.

Followed by some time spent in the town with many details just not making sense. Servants living in a mansion with no owner, houses with multiple beds occupied by a single person, children's play room in a house where the family claims to have never had kids, etc.

Have one night a player awoken to a scream, come down stair to investigate and the house owner (inn keeper?) in their in the living space, front door wide open, signs of a struggle, but assuring nothing is wrong and they are just cleaning up (everything is in clean order by morning).

Come morning, some details are made clear to the party that something's off about the inn. The owner's rooms were built and furnished for more than just them (spouse, kids, etc) but when questioned the owner says they've been single their whole life.

To really mess with the party, they return to their rooms one day and there's an extra set of gear with their belongings, as though there was another person in the party they just don't remember. The belongings have a diary or some form of notes that detail a connection with the group, as if the person travelled to this town with the party, possible having travelled with them for a long while before that too. These belong to a person that WAS part of the group, but no one can remember them, all memories of them have been wiped from their mind. The key part here being the players IRL have no actual recollection of the events that were changed because they were never part of a real prior session, it's just in story to have actually happened and all of their characters' minds were altered.

From here on you can direct the players onto a method of shielding their minds and now get to start with saving throws, getting to see the details that they cannot remember, slowly unravelling the horrors behind the altered memories, discovering the False Hydra and slaying it before it wipes out the town.

[MoiMagnus]

Most players are usually ok with railroading when it is used to setup a plot, as long as they then have agency to resolve it as they want (and that the setup is not a significant portion of the scenario).

How I'd handle a railroaded session because of memory modifications:
1) The memory modification is in multiple steps, meaning that just one successful save doesn't unravel the whole story. Probably one or two red hearings too.
2) Along the railroaded session, if things really go out of the rails, I might at some point "order" a PC to act differently to what they would plan to (either through messages, or private discussions), essentially saying "A posteriori, this course of action will seems unnatural to you, you don't know why you did it. Remind me that you have a HINT during the upcoming investigation phase, and please keep this discussion secret until the end of the session.". In general, I'd essentially treat the session as if they were constantly under the assault of major illusions and mind controls. The more I'm forced to railroad to reach the expected point, the more in-universe the artefact had to modify memories, so the more they get will get hints for the investigation phase when they will try to unravel the truth.
3) Don't drag into length. Don't hesitate to narrate some moments rather than playing it. Possibly using sentences like "I supposes that now that you did that, you continue by doing this and this?".
4) When the PCs reach the moment where the memory modification would have happened, they get a save, and win a HINT if they succeed. Then, during the next short or long rest, by talking individually to each player, I'd convert the hints into partial informations about what really happened. I've talked earlier about red hearings, hint should always give at least one "true" information, but can sometimes also give misleading/false infos on top. If we're at the end of the session, and that the session did not at all as planed (which it of course will), I might postpone those hints to the next session so that I have the time to craft them correctly rather than improvising them.
5) I'd be open to creative solutions suggested by the PCs to get additional hints.

[Pex]

You have to really, really trust your players to trust you. Players can only know about the world as the DM tells them. It can be acceptable when an NPC lies to them. The players will hate the NPC, but they recognize it's the NPC who lied. When it's the DM who lies that breaks trust. Players do not want to be manipulated. When players do not believe what the DM tells them the game is over.

[Galithar]

I just wanted to address, that this is part of a long on going plot within the world. While there is a small chance the players will succeed on a save and get a hint early, if they all fail they will not have a chance to discover this in recent times.

The reason that this has such a long time table is because I expect the event to be big enough that multiple players will remember the event well even when the modification isn't revealed for potentially months (additionally I will be taking extremely detailed notes myself and the revelation will come with a play by play retelling by me with the corrected details). I am going to be attempting to build up slowly to the revelation that they are being manipulated by someone. The modified memory is only part of it. Other parts will be from modified memories on their allies (these will just happen, no save, because they are NPCs and I need them to progress part of the story) and from straight deceptions. The idea is that (other than the sentient item) the BBEG is actually not that imposing. They are a mid power spell caster, but they are extremely intelligent and manipulative. They affect change on the world from the shadows and with minions.

[JackPhoenix]

I don't think Modify Memory is going to do the trick as described. It only affects one target, and it takes a minute to describe what the false memories are... anyone unaffected isn't gonna just stand there. It's unusable in combat. And, given how it works, even if the characters are caught individually outside combat, different characters would "remember" some things differently, unless the caster was super-specific (and again, he's only got 1 minute to describe the false memories).

[Galithar]

I don't think Modify Memory is going to do the trick as described. It only affects one target, and it takes a minute to describe what the false memories are... anyone unaffected isn't gonna just stand there. It's unusable in combat. And, given how it works, even if the characters are caught individually outside combat, different characters would "remember" some things differently, unless the caster was super-specific (and again, he's only got 1 minute to describe the false memories).

It's almost like I knew it was a single target spell and made a HomeBrew artifact that the campaign will revolve around that is sentient and gives it an AOE.

The false memory will take less than 30 seconds to put in place. And it wouldn't be remembered differently because it's modifying an existing memory with false details that will be described the same (even if it used multiple castings... Which it won't)

[Keravath]

The biggest issue you might have is consistency.

You have to make sure that every event the players have before and after the altered memory is consistent with it.

They were looking for some object. They expect to find it with an opposing organization and are surprised to find it with their allies. A fight immediately breaks out as the "allies" attack?

Nope - too many inconsistencies - the bodies after the fight will be those of allies not enemies. The party has to lose or at least whatever their goal was escapes. If they win and recover what they were looking for ... what was the point of the "allies" involvement at all if they were going to let the party take the item anyway?

A scenario that could work - the party finds their "allies" have just defeated the "opponents" and are making off with the item. Memories are re-written so that the party has just defeated the "opponents". However, the party requires some wounds otherwise that won't be very believable after the fact either.

Requirements:
- altered memory
- dead bodies consistent with the weapons and spells used by the party from the correct opposing faction
- damage to the PCs consistent with the outcome of the battle they remember.

You can't damage the PCs while they are under the effect of modify memories
"If it takes any damage or is targeted by another spell, this spell ends, and none of the target's memories are modified."

---

If the spell is cast at a higher level ...
"At Higher LeveIs. If you east this spell using a spell slot of 6th leveI or higher, you can alter the target's memories of an event that took place up to 7 days ago (6th levei), 30 days ago (7th levei), I year ago (8th levei), or any time in the creature's past (9th levei)."

So .. if the fight is the last thing before a long rest, then the spell could be cast during the long rest so that when they wake up at full health they would not notice that the fight did not damage them. However, you'd have to make sure that the party didn't do anything lasting with the information they would have received from the real fight.

However, you still need to make the changed memories consistent with what the character remember from before and after the encounter. If you have them remember a fight and also not remember having any wounds from after what was supposed to be a fight then there is a problem. If they have a fight but the bodies are not the ones they would expect from the opponents then you have a problem. You only have a 10 minute window to try to blend the memories in to whatever they actually do remember and to do that in a logical and consistent way which is needed to make it seemless in a role playing sense, won't be easy.


---

If you can get the details correct then I think many players would accept the use in this context when they learn about it after the fact.

However, you have to be prepared for
1) Someone making their save. Even a DC24 can be made by a character proficient with wis saves and a 16 stat on a 19 or more. A DC of 22 brings this down to a 17. Depending on the characters it isn't that unlikely that someone would make their save then there will be two memories of the event (though this could also be fun). If this happens, try to make sure that the real memory might be suggestive but not give everything away.

2) Any remove curse or greater restoration cast on the character will fix the memory. So if they get cursed for something else or restored for something else the memory will also go and you will need to remember that and take it into account.

Its doable but you will need to really work on the consistency.


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Possible actual scenario - players find "allies" have just killed "opponents" and taken the item. Players start to attack "allies". "Allies" trigger a trap causing the room to start to collapse, entrance is blocked by fallen rubble, characters have to dive into shafts out of the room to escape - falling down the shafts causes damage as they bounce off walls. Characters may have taken a bit of damage from a round or two of combat. "Allies" escape with whatever the goal was.

Modified memory scenario - players enter area find "opponents" with item. Fight ensues. "Opponents" trigger a trap to collapse the room and try to flee. Some succeed, escaping with whatever the item is. The characters have to dive out the shafts from the room to escape the collapse.

Entire memory of the room fits in less than 10 minutes. Room is destroyed and evidence gone. Characters are damaged consistent with fight and descent in shafts. Fake memory is consistent with the experienced reality.

However, you have to make sure that the entire encounter is over in 10 minutes and no evidence remains. You could make the trap and required hasty exit part of the modified memory except that the party has to have a memory that continues after that 10 minute window that is consistent with the revisions.

[JackPhoenix]

However, you have to be prepared for
1) Someone making their save. Even a DC24 can be made by a character proficient with wis saves and a 16 stat on a 19 or more. A DC of 22 brings this down to a 17. Depending on the characters it isn't that unlikely that someone would make their save then there will be two memories of the event (though this could also be fun). If this happens, try to make sure that the real memory might be suggestive but not give everything away.

It's worse than that: whoever made the save will be aware and able to act for the time it takes to describe the fake memory, they'll remember not only the original memory, but the villain casting the spell. They'll know exactly what happened. They can attack the villain, break his concentration, or wake the other characters. Or just ensure everyone will receive Remove Curse at the earliest opportunity.

[Galithar]

Keravath makes a good point for checking consistency, so let's see if anyone can see any inconsistencies in the proposed scenario.

The group is sent to investigate a set of ruins by their employer (a university interested in a potential relic). The party arrives to find Organization Y already on site. Organization Y was attacking and killed the existing members of the University that were on site waiting for the adventurer escort as they had been attacked by golems (ancient defenders of the ruins that had previously been trapped but we're released during excavation). Organization Y is also looking for a relic. The party encounters them, fights and presumably wins. Now if they somehow lose, or retreat or whatever the. BBEG will come up with a different plan. This is just Plan A that I'm coming up with in advance because I don't have the 20 Int that the BBEG does. After the party leaves, but BEFORE they return to civilization they have memory modified to think they encountered and killed members of organization X. A group that is at the time on neutral standings with their university and home city. This causes strained relations when this is reported. They return with the relic they were looking for. Organization Y doesn't take the relic, because while it is ancient and powerful (Rare magic item level... Exact item not decided. But not the Legendary artifact the BBEG was looking for) the BBEG decides that masking his involvement and blaming someone else will do more to help him mask his dealings. To do so he has to leave the party alive and in possession of the relic they recovered.

[MaxWilson]

I have an idea I would like to use against my players. I have a bad guy that would want to manipulate the players with a modify memory spell. Now, I don't want the players to have any knowledge of the original event, and the modification would be changing WHO was involved in an event, not the actual outcome.

So my idea is this, I would have them roll the save at the beginning of a session (before the events that would be modified) Now this would be a high level enemy with a high save DC manipulating the party while they are at a low level. The chances of a successful save are low, but I would abide by a success (The person(s) that saved would privately be given a different accounting of the events after the full resolution).

This is slightly railroady, because I am not giving them the possibility of avoiding the casting of the spell. I feel this is well within the realms of possibility as the caster also has access to scrying and other magics to make sure this happens.

My question is this, as a player when you inevitably find out your memories were modified would you find how I did this cool? Or annoying? Do you have a suggestion to do this better?

I am inclined to find it cool, I think, although I'm not entirely sure what the part in bold here means, and if I were you I'd give them a little note or something immediately when they made the save saving something like "what I'm describing here didn't actually happen exactly this way, it was really [XYZ]--don't tell anyone until the session is over, and I will answer any questions you have then". Good luck making it work!

[BruceLeeroy]

I've done this, or rather, something like it, with memory-unreliability, by simply fast-forwarding a chunk of time, telling each of the players a different account of the gap, and having them figure it out/try to reconstruct collectively over a span of 3-5 sessions. That way it was presented as a puzzle, rather than me describing how they are being mind-raped and asking for saves, etc. That part felt like it would suck to happen more than a time skip+mystery memories.

This was all based on a slightly modified intellect devourer rather than modify memories spell, but it's the same thing, from a handwavey-cutscene point of view.

[Galithar]

I am inclined to find it cool, I think, although I'm not entirely sure what the part in bold here means, and if I were you I'd give them a little note or something immediately when they made the save saving something like "what I'm describing here didn't actually happen exactly this way, it was really [XYZ]--don't tell anyone until the session is over, and I will answer any questions you have then". Good luck making it work!

The reason they won't be given the true accounting of events immediately is because the saving throw will be rolled in advance. Long before the actual spell is cast. Beginning of the session it will be cast as opposed to giving them an inkling of when it happens. It will also be told to them when they make the save that I'm asking for it now because as long as everything goes as expected I don't want you to know when the effect starts. If your actions prevent this from happening then the save will be discarded. I then intend to try to make them THINK they knew what the save was for. That's more of me trying to obfuscate from the player than any interaction with the game world though and I might bypass the attempted cover up and just say "please don't try to figure out what this save is for".

[Lunali]

I have yet to meet a DM that I felt confident in their ability to keep track of everything anyone at the table could possibly do to alter their chances of making a save. Some characters are immune to certain effects, some will have advantage on certain saves, some have reactions that they can use to improve their saves, some have abilities that remove certain effects. If want to keep the source of the save a secret, you become responsible for keeping track of all of these.

[Galithar]

I have yet to meet a DM that I felt confident in their ability to keep track of everything anyone at the table could possibly do to alter their chances of making a save. Some characters are immune to certain effects, some will have advantage on certain saves, some have reactions that they can use to improve their saves, some have abilities that remove certain effects. If want to keep the source of the save a secret, you become responsible for keeping track of all of these.

Luckily those things you claim are common are actually extremely rare and almost none of them are available at level 3-4 when this is most likely to occur.

And I regardless of your confidence, I am very diligent in my research into rules and know my players abilities inside and out. I spend a lot of time going over material and am completely confident that none of them have any ability that can modify a Wisdom saving throw that I don't know about. For example the Loxodon Paladin will have advantage on his saving throw. I will not be telling him this, but I will roll the advantage in secret.

No one else currently has anything that will effect this save (modified races, Elves no longer have Fey Ancestry granting advantage against the charm effect)

5e doesn't have loads of finicky +/-1s to keep track of and simply having them roll a Wisdom save means that 90+% of the potential modifiers will be accounted for already. What else is going to effect this? It's a bunch of half casters at low level at the beginning of a campaign. If your DM can't keep track of the race your playing then you might have bigger problems.

[Lunali]

To be honest, this plot sounds fun for exactly one person and has the potential to completely destroy all trust between the DM and the players.

[Keravath]

Luckily those things you claim are common are actually extremely rare and almost none of them are available at level 3-4 when this is most likely to occur.

And I regardless of your confidence, I am very diligent in my research into rules and know my players abilities inside and out. I spend a lot of time going over material and am completely confident that none of them have any ability that can modify a Wisdom saving throw that I don't know about. For example the Loxodon Paladin will have advantage on his saving throw. I will not be telling him this, but I will roll the advantage in secret.

No one else currently has anything that will effect this save (modified races, Elves no longer have Fey Ancestry granting advantage against the charm effect)

5e doesn't have loads of finicky +/-1s to keep track of and simply having them roll a Wisdom save means that 90+% of the potential modifiers will be accounted for already. What else is going to effect this? It's a bunch of half casters at low level at the beginning of a campaign. If your DM can't keep track of the race your playing then you might have bigger problems.

No gnomes? No Yuan-ti purebloods? No clerics habitually walking around casting resistance?

As for continuity in your scenario. The PCs arrive and find organization Y. They watch/investigate/talk/have a fight. They hang around and search afterward, loot the bodies. The problem is that they see and interact with Y for likely more than 10 minutes. The actual battle may be less than a minute but the entire encounter from arriving and encountering Y until they leave is likely much longer than the 10 minutes that can be changed using modify memories.

They remember finding Y, for some reason remember fighting X, however, at the end of the memory it is Y bodies they loot for the next 30 minutes or more.

You only have a 10 minute modification window unless you massively increase the power of this artifact by increasing the length of memory that can be affected ... which then slides into making the tools fit your idea whether the players would find it fun or not. You also then need to account for why the BBEG wouldn't use it to simply erase any memory of them entirely all of the time. Harder to fight something that no one remembers.

The BBEG will be using it all the time.

Did you intentionally remove the resistance to charm effects from Fey Ancestry in order to use this trick more reliably - since modify memory causes the charm effect, creatures that are resistant or immune would either have advantage or be unaffected.

[Galithar]

No gnomes? No Yuan-ti purebloods? No clerics habitually walking around casting resistance?

As for continuity in your scenario. The PCs arrive and find organization Y. They watch/investigate/talk/have a fight. They hang around and search afterward, loot the bodies. The problem is that they see and interact with Y for likely more than 10 minutes. The actual battle may be less than a minute but the entire encounter from arriving and encountering Y until they leave is likely much longer than the 10 minutes that can be changed using modify memories.

They remember finding Y, for some reason remember fighting X, however, at the end of the memory it is Y bodies they loot for the next 30 minutes or more.

You only have a 10 minute modification window unless you massively increase the power of this artifact by increasing the length of memory that can be affected ... which then slides into making the tools fit your idea whether the players would find it fun or not. You also then need to account for why the BBEG wouldn't use it to simply erase any memory of them entirely all of the time. Harder to fight something that no one remembers.

The BBEG will be using it all the time.

Did you intentionally remove the resistance to charm effects from Fey Ancestry in order to use this trick more reliably - since modify memory causes the charm effect, creatures that are resistant or immune would either have advantage or be unaffected.

Party is a Warforged, Wood Elf, Loxodon, Goliath and one as yet undecided.

Removal of Fey Ancestry is due to the fact that Elves in my world have no relation to the Fey. I don't know why you are fixating on something I've already addressed, but perhaps it's simply good that you're not in my game. You seem to have a very inherent distrust towards DMs and that's not a problem my group has.

I maintain their trust, even when I break the rules, by being honest with them. I once faked a crit to down a player. The player knew it was coming the rest of the party didn't. The second the situation was resolved I told them exactly what was done and why. The player had an idea for character development that required them to go down, and so I agreed to work with them to fabricate the situation. No one was upset, and it was one of the players (who was in the dark about it) favorite moments.

[Lunali]

I maintain their trust, even when I break the rules, by being honest with them. I once faked a crit to down a player. The player knew it was coming the rest of the party didn't. The second the situation was resolved I told them exactly what was done and why. The player had an idea for character development that required them to go down, and so I agreed to work with them to fabricate the situation. No one was upset, and it was one of the players (who was in the dark about it) favorite moments.

Fudging dice to help with cooperative story telling is very different from railroading a party into following your story.

Also, you left out the other things that can happen besides a saving throw. For example, if the caster fails to beat passive perception with stealth (or passive insight with deception if you have house rules for social surprise) the party will have a chance to beat him on initiative, changing their positions and possibly making it impossible to catch all of them in the AoE.

[Galithar]

Fudging dice to help with cooperative story telling is very different from railroading a party into following your story.

Also, you left out the other things that can happen besides a saving throw. For example, if the caster fails to beat passive perception with stealth (or passive insight with deception if you have house rules for social surprise) the party will have a chance to beat him on initiative, changing their positions and possibly making it impossible to catch all of them in the AoE.

Intentionally left out because it had nothing to do with what I was asking about. I don't have the time or desire to explain the entire encounter and how things play out and all of the rulings I use. Suffice to say that the level of magic available to the perpetrator is vastly overpowering the potential of the party to detect them. With the main thing being the BBEG knows where the party are and the party doesn't even know the BBEG exists.

The situation and the reaction to it, and advice for how to improve the story is what I'm asking for. The mechanical implications I am plenty capable of addressing.

And though I said I wouldn't, here's why they can't detect the BBEG they have no knowledge of:
Highest possible Passive perception is 21. +4 ability, +2 prof, +5 observant. They will have disadvantage dropping that to 16 due to darkness. The BBEG will have Pass Without Trace and a natural +7 to stealth. Making their minimum roll be a 18. The highest possible Passive is beaten by the lowest possible stealth. Additionally with no Wisdom casters the likelihood of a +4 Wisdom at level 4 is low.

The BBEG has had stats since long before I came up with this scenario. Sneaking and manipulating from the shadows is kinda his jam.

Also as I've said before, if they somehow bypass the circumstances then this doesn't happen. It's a scenario, not a rail. It's just one that I've calculated had a high probability of coming to pass and an preparing accordingly. It's also possible that the party never takes the job in the first place and the BBEG simply recovers the relic and that team from the University is later found dead.

[Keravath]

Party is a Warforged, Wood Elf, Loxodon, Goliath and one as yet undecided.

Removal of Fey Ancestry is due to the fact that Elves in my world have no relation to the Fey. I don't know why you are fixating on something I've already addressed, but perhaps it's simply good that you're not in my game. You seem to have a very inherent distrust towards DMs and that's not a problem my group has.

I maintain their trust, even when I break the rules, by being honest with them. I once faked a crit to down a player. The player knew it was coming the rest of the party didn't. The second the situation was resolved I told them exactly what was done and why. The player had an idea for character development that required them to go down, and so I agreed to work with them to fabricate the situation. No one was upset, and it was one of the players (who was in the dark about it) favorite moments.

I don't have any issue with DMs or with you personally. It is a cool idea. My biggest concern is somehow making all the before and after memories that the characters would have consistent with the 10 minutes you have to edit. If they remember fighting X but also remember Y corpses when they search them in the 30 minutes after the battle (or if they later walk through the room). Then their memories will be inconsistent and there is a good chance they would notice since sometimes they remember fighting X and sometimes they remember looting Y or seeing Y when they return through the room.

As a DM, trying to implement this kind of switch in a way that the characters find consistent when playing it, you really need to make details consistent or simply decide that the artifact can modify any length of memory it wants to and is not constrained by the spell description. Unfortunately, the latter is a bit of railroad if the DM creates a situation from which the players have no escape and no way of knowing it is happening. In addition, if the artifact is that powerful then the BBEG will use it all the time and no one will ever remember them.

Plotwise, you could probably add an anti-magic chamber or zone which the BBEG is unaware of in one of the dungeons/adventures and when the characters enter they fall to the floor in shock as all their altered memories come flooding back. (since the BBEG probably can't resist altering more than one ... he might even have had megalomanical chats with the characters knowing they will never remember after he is done and can gloat about them doing his work for him.