11th Level Mystic Arcanum, Celestial Warlock - the Tyranny of Choice

[KorvinStarmast]

I am trying to plan ahead since our DM indicates that our campaign may get as far as 11th level. (There's a big bad out west whom we will eventually confront, but at the moment we have a local threat of an orc army invasion, a local despot who has been terrorizing villagers, and a legacy sword we need to find so that the true king can be restored.

But when I get to 11, I look at my choices (PHB only considered so far, not sure what XGTE spells qualify) I can only pick one. For some reason, I had thought that after a long rest I could pick any one of them, but as I re read the Mystic Arcanum text, that seems a bogus assumption on my part.

So here's what I've got so far; Rank Ordered in a rough first cut.

1. Arcane Gate (conjuration); This looks like a really neat mobility option once per day. Very tempting, and it is somewhat on theme with my support role.
2. Eyebite (necromancy) WIS Save:Tempting way to support our martial damage dealers by disabling enemies.
3. Conjure Fey (conjuration) If I could up cast, yeah, but I am not sure if CR 6 creatures will help us.
4. True Seeing (divination): This is a really good spell for enemies who do inviso and illusion shennanigans.
5. Flesh to Stone (transmutation) CON; tempting but the CON save concerns me.
If you maintain your concentration on this spell for the entire possible duration, the creature is turned to stone until the effect is removed.
6. Mass Suggestion (enchantment): I already have Fear as a contro spell. Not seeing how this is an improvement. But since we are dealing some times with large numbers of enemies (no, I can't up cast this) maybe this has utility?
7. Create Undead (necromancy) - Interesting spell, but I'm not playing evil, I am pact of the tome Celestial. Thematic? Not there. More importantly, our Wizard has personal objections to people using undead on our side, so this one's not really on the table. Group harmony and all that.
8. Circle of Death (necromancy) : not feeling it, and there we go: Con Save. Still, against mobs, it's as good as fireball cast as a 3rd level spell. :smallyuk: I already have Wall of Fire.

Playgrounders, I could use your advice.
What have Warlock 11+ characters that you have played chosen as Mystic Arcanum picked? And please share the "why this was my pick" - the XGTE spells are also eligible.

[airless_wing]

Arcane Gate all day. Portals are just too much fun, and the solution to so many problems. By lvl 11, your Warlock will have crazy upcasting powers for any AOE spells, and plenty of single target DPS with Eldritch Blast, so picking up fun & useful spells for your Mystic Arcanum seems like the most fun way to go. There's almost no situation, other than a straight slugfest, where Arcane Gate wouldn't be a good choice imo.

[Bobthewizard]

Mass Suggestion is my favorite 6th level spell. 12 targets and doesn't use concentration. You can use it after Fear on anyone that made that save.

If you have XGTE and your DM makes positioning important in battles, then Scatter can be a good spell.

[P. G. Macer]

I only got to Level 10 with my Celestial Warlock before the game fell apart, but if I’d gotten to 11, I’d have picked Investiture of Flame from XGtE, since it combines with Radiant Soul.

[Zuras]

The Hexblade in my last campaign picked up Soul Cage and had fun with it. It’s probably a little dark for a Celestial, but would be handy for intel gathering.

[KorvinStarmast]

Arcane Gate all day. Portals are just too much fun, and the solution to so many problems. That's kind of where my brain went initially.
Mass Suggestion is my favorite 6th level spell. 12 targets and doesn't use concentration. You can use it after Fear on anyone that made that save. Ooh, nice catch there.

I only got to Level 10 with my Celestial Warlock before the game fell apart, but if I’d gotten to 11, I’d have picked Investiture of Flame from XGtE, since it combines with Radiant Soul.I already have wall of fire and it will be cast at 6th level at that point. I will go and read that spell again and see ...
The Hexblade in my last campaign picked up Soul Cage and had fun with it. It’s probably a little dark for a Celestial, but would be handy for intel gathering. Soul Cage? Hmm, if we capture evil NPCs or monsters maybe I can use that. Checking spell details. Hmm, six doses of advantage ... hard to resist.

Thanks to all, good ideas so far.

[clash]

Can I recommend mental prison from Xanathars.
It provides guaranteed damage and great control on an intelligence save, which is one of the weakest saves for monsters, and if they escape, they take more damage.

[KorvinStarmast]

Can I recommend mental prison from Xanathars.
It provides guaranteed damage and great control on an intelligence save, which is one of the weakest saves for monsters, and if they escape, they take more damage. That's got potential; I'll need to check on what kind of enemies we are fighting when we get to that point in the campaign.

[Evaar]

For Mystic Arcanum, if possible I like to pick spells that impact more than a single encounter and have broad use.

This is a somewhat arbitrary distinction, because if you end an encounter with Mass Suggestion by telling the enemies to flee until the next dawn, then you saved all the resources that encounter would have expended and thus have impacted your adventuring day.

So I'm not saying that this is the most powerful way to approach it, just how I like to approach it.

I find that having a big gun like Mass Suggestion means I'm constantly asking myself if this encounter warrants using it, or if I should save it. Instead, if I use something like Soul Cage, I'm looking for my first chance to cast it and then I have those benefits on demand for the rest of the day whenever I want them. If you're a Celestial, it doesn't have to be evil; you can be trapping the spirits of evildoers and giving them a chance to do some small penance before they transition to the afterlife. If anything, that might be merciful. And it has a lot of useful options - healing, intelligence gathering, or just on-demand advantage.

Conjure Fey lasts an hour, you can summon up a big nasty Annis Hag to fight for you through multiple encounters. Or you can summon a Quickling if you need a scout. Or a Pixie if you want something to cast Fly, Polymorph, Confusion, Phantasmal Force, and Dispel Magic without you having to spend spell slots or concentrate. If you can use Mordenkainen's Fiendish Folio, a Forlarren can cast Heal which is a 6th level spell on its own, then it can cast several other spells after that. Unfortunately most Hag spellcasting comes from being in a coven, which you can't really use with Conjure Fey. But even so, I think you can see above how you can make use of several Fey creatures.

Eyebite deserves some special mention because, even though it only lasts a minute, you're using it for that entire minute. It's giving you three good options for your Action for the following minute, including just putting a target to sleep over and over - note that if it wakes up from taking damage, that does not mean it succeeded on a saving throw so you can just target it again.

To my mind, the worst choice is something that targets one creature and gives it a chance to save. That's that slot done for a day, and you can't change it. And then something like True Seeing is a little too niche unless you're in a game where you know it'll always be useful.

[Chaos Jackal]

Warlock's 6th-level options are for the most part either situational or weak.

There's a couple picks which, in my opinion, are flat out better, carrying a lot more advantages and a lot less disadvantages than the other spells available. Mass Suggestion and Soul Cage. Going with these, outside of the specific circumstances mentioned below, is typically always gonna result in the Arcanum having value.
Mass Suggestion is generally the most powerful option. Suggestion is a versatile spell in the first place. This has no concentration requirement, twelve times the targets with no friendly fire, and lasts three times as long. For an effect that grants no repeat saves, can be used both in combat and social situations, and is pretty powerful on top of it. There just aren't many spells of any level that combine all these things. From sending the enemy mooks on a lunch break to swaying the merchant council's majority vote to your favor, Mass Suggestion can do the job. Unless you're expecting a lot of charm-resistant opponents (say, commonly dealing with moderate/high CR undead), Mass Suggestion will find use every day. Even if you frequently encounter charm-resistant enemies, you can still find opportunities to use Mass Suggestion. You just can't go wrong with it. A ton of uses with almost no drawbacks, it's the one 6th-level warlock option that is truly good and one of the best spells in the game in general. A league of its own.
Soul Cage is also a good pick, for similar reasons. Long duration, no concentration, plenty of utility, can be used in and out of combat. It has a few more problems compared to Mass Suggestion though. For one, it requires combat. It might last you into the social meeting afterwards, but first something near you must die. The second is that it only works on the souls of humanoids, so if you're expecting, say, a lot of demons, there're gonna be many days where it won't find use. And the third is that its effects aren't very powerful. The power is in the number of options, but the options can feel underwhelming.

For more situational spells that will still be used regularly, there's Mental Prison, Conjure Fey, Scatter and Create Undead (which I won't delve into because you don't want to take it). Taking these isn't a bad idea. They don't cover as many situations as the aforementioned two spells, or aren't as reliable, but they're good for covering some goals. If you want coverage in one of their areas, they are good.
Mental Prison is a powerful disable targeting the uncommon Int saves, with a powerful damaging component using psychic damage, and at least shaving off some HP even if the enemy saves. As far as single-target save-or-sucks go, it's top-notch. However, single target save-or-sucks aren't always very potent, especially when they take your only 6th-level spell of the day. If you want to reliably take someone out of combat while nuking them for Disintegrate levels of damage, then this is golden. But if it's just the disable you're after, you can already do that with something like Banishment, or Fear/Hypnotic Pattern.
Conjure Fey carries the risk of losing control, and you won't be able to summon very powerful creatures with it. However, it does give access to a number of spell battery monsters, allowing for some extra utility, and worst case scenario you can just summon a mammoth or dinosaur as a tank. So not very powerful, takes concentration and losing it has consequences. In return, it can be used in many situations, in and out of combat. It also lasts an hour, so you can summon your creature ahead of time and milk it for all it's worth.
Scatter has the decent effect of rearranging the battlefield. It's held back by the effect being just decent (no dropping people off cliffs) combined with a crappy range. If it had a stronger effect, or if it had better range, I could see it being a lot more useful. It's still teleporting 5 creatures 120ft each though, and they can be any combination of allies and enemies. You can find uses for that.

Then you have a number of more niche spells. These are limited in scope and are generally not worth it, unless you believe their specific niches will come up often. They include Arcane Gate, Eyebite, Investiture of Fire/Stone and True Seeing.
Arcane Gate seems nice at first glance, however it has a combination of flaws that make it quite ineffective in many scenarios. The most obvious one is the concentration requirement. Worst case, this can strand allies and make things really tough for them. It also requires line of sight to wherever you open the second portal, so no using this to bypass walls, doors or even going around a corner. 500ft is a lot of distance, yes, but unless you commonly find yourself fighting at long ranges in open environments, it won't come up. And it has no restrictions to who can use it, so initiative order can really mess it up, as it will end up providing mobility for enemies too. It can allow for some fun tricks, but it can also turn out to be detrimental.
Eyebite is another single-target disable. It has repeated uses, however it takes both your action and your concentration. I find it quite a steep price to pay for a spell of its level. If you want to affect multiple enemies, just drop a Fear or Hypnotic Pattern and save your future actions. If you want a single-target disable, throw a Banishment or a Mental Prison. Yes, Eyebite can do both, but it also takes a lot more resources to do so, and you can easily cover its areas. Worth it only if you don't find its cost too much. This is probably the spell I'm underestimating the most.
Investiture of Fire could be somewhat useful, at least it's immunity to a common type of damage, and while weak damage to attackers isn't great since you'd prefer to avoid being attacked in the first place, it's something at least. The active effect is bad for the most part, but it could come up. And it's better than Stone's. It's also 10 minutes, but concentration holds it back in that regard.
Investiture of Stone has a couple decent effects. Physical resistance isn't bad, and neither is moving through rock. However, it's concentration, the tremor effect is terrible, and if you're facing magical weapons or spells, it becomes a lot less useful overall. It's not awful, but it's not amazing either, and can easily be made largely irrelevant.
Finally, True Seeing is almost textbook niche. Takes no concentration, lasts for an hour, and is excellent at what it does. The problem is, it's not something that comes up often. It's a typical "9/10 it's useless, 1/10 it's incredible". If you believe it's going to be more common, or have no other defense against invisibility and illusions, go ahead.

And then you have a number of spells that are just bad and not worth it. Circle of Death, Flesh to Stone, and the other two Investitures.
Circle of Death does Fireball damage, except with a better damage type and massive area. But if you're using a 6th-level spell just to deal 8d6 damage, and on a Con save to boot, then you're either facing armies of weaklings all the time, or you chose wrong.
Flesh to Stone is a save-or-restrain, then save-or-die. Only issue is, it's a Con save. And a repeat one at that. Restraining a single target isn't worth it for a 6th-level spell, and actually petrifying the enemy is quite unlikely.
The remaining Investiture spells pack a number of weak effects on a 6th-level concentration spell, which just doesn't work. Ice is typically inferior to Fire on its elemental resistance part, its difficult terrain has a small range and also affects allies, and the active effect just doesn't cut it. As for Wind... well, flight is great, except you can use the Fly spell, which is cast on 5th level since you are a warlock, to buff the entire party for the same duration. The active effect is dreadful too. The only somewhat decent part is the protection from ranged attacks, but if you're casting a 6th-level spell for that, it feels wasteful.


Edit: Regarding Mass Suggestion, I should have noted that it is a DM-dependent spell. "Obviously harmful" is subjective and a DM is likely to interpret it as more than just self-mutilation, which is the case of listed examples. However, there's still a number of mostly harmless suggestions to make, even in combat, depending on the situation at hand, as long as you're creative. If your DM outright dislikes the idea of combat Suggestions though, then the spell loses value in combat-focused games, because it will simply never work. So be mindful of that.

Edit 2: Conjure Fey is also DM-dependent, so you might wanna ask them on summons, because if they end up doing a random roll or something, you'd better skip it.

[Contrast]

I already have wall of fire and it will be cast at 6th level at that point.

I don't know if that was a typo but in case not, just a reminder that the regular warlock spell slots cap out at 5th level.

[Zuras]

I’d also add that Investiture of Stone can be amazing on a Melee Warlock, especially if you are still doing traditional dungeon delving in Tier 3, but given your description as a support character, it wouldn’t be helpful for you. Handy in Undermountain, though.

[Tanarii]

You guys keep recommending Mass Suggestion. Are you really in that many large scale non-combat encounters with creatures every long rest? Suggestions aren't particularly useful as a combat spell.

[Chaos Jackal]

You guys keep recommending Mass Suggestion. Are you really in that many large scale non-combat encounters with creatures every long rest? Suggestions aren't particularly useful as a combat spell.

If you can't use Suggestion in combat, then you're either not very creative, or the DM is especially adversarial.

Suggestion does fall into the uncomfortable zone of spells that are ultimately up to the DM to decide, since "obviously harmful" is subjective. The examples given in the spell's description basically equal "obviously harmful" to "self-mutilation", but that won't be the case in every table.

But as far as combat is concerned, there's things to suggest during it or before it, and without resorting to cheesier approaches like "I'm with you on this, I suggest you follow my commands".

"This armor is very cumbersome/heavy/makes you very hot. You'd fight more comfortably without it.", "This skirmish could get you killed. Better go home and make dinner/head to the tavern for a drink/return to camp for a nap.", "You should be paid more for guarding this gate. It's not worth fighting us for so little money.", "Your lord might be under attack too. Protecting him is more important than protecting the treasure room.", are all possibilities, and there are a lot more, depending on the situation, what enemies you're facing and what you know about them.

Not every Suggestion will fly at every table, just like not every illusion will fly at every table. And as is the case with illusions, if your DM decides he doesn't want Suggestion to work, it won't work. But unless they're really against it, they'll allow something.

So yeah, if your DM stretches "obviously harmful" as much as they can, then Suggestion is bad in combat and a lot more limited out of combat too. But in many cases you should be able to use it effectively.

[Skylivedk]

That's kind of where my brain went initially. Ooh, nice catch there.
I already have wall of fire and it will be cast at 6th level at that point. I will go and read that spell again and see ... Soul Cage? Hmm, if we capture evil NPCs or monsters maybe I can use that. Checking spell details. Hmm, six doses of advantage ... hard to resist.

Thanks to all, good ideas so far.

I took Soul Cage with my Hexblade. Mass Suggestion seemed a better fit for our bard and not being able to upcast it (why, WotC?!?) meant it lost a lot of allure. Soul Cage was extra nice because:
A) my team mates had a tendency to forget taking prisoners (so much intel lost as my character would yell: "Don't jul the la... F***!")
B) as I read it it combines extremely well with synaptic state since you don't need line of sight for Synaptic State. Process as follows:

1. Enter bad guy area (dungeon, castle, temple, etc).
2. Kill first group of goons.
3. Capture soul of highest ranking goon/goon who has presumably seen most of bad guy area.
4. Use the Soul Cage's eyes of the dead to look into rooms/towers/walled of areas you want to enter.
5. Once a room with waiting ambushers/more goons are concentrated in numbers, proceed to apply liberal castings of Synaptic State until most of the room is dead on the floor and bleeding out their ears. Any survivors are probably hurt and debuffed.
6. Mob up.
7. Coffee break.
8. Repeat.

The whole thing becomes even more fun with minor illusions thrown in for sound effects to cause some widespread panic (works extra well with cults: divine punishment)

[Mr Adventurer]

I've used Suggestion on a troll that interrupted a battle we were having with bandits: "This is dangerous, you'd be much better off going back to your den and waiting, then coming back and feasting on the bodies!" This worked and sent the troll away.

I've used it on a green dragon: "You're so powerful, you don't need to use your breath weapon on us, you can just kill us with your claws and fangs!" This worked and meant the dragon closed with us for melee rather than using its breath weapon, which was a much better option for us.

You need to co-ordinate with your party a little so they don't attack and break the suggestion right away, and accept that you might not get the full spell duration. But it's got plenty of use.

[LudicSavant]

2. Eyebite (necromancy) WIS Save:Tempting way to support our martial damage dealers by disabling enemies. I don't really see the attraction for Eyebite. You can't get extra tries against a single target, and you can't hit multiple targets in a single round, and its effects are relatively mild.


3. Conjure Fey (conjuration) If I could up cast, yeah, but I am not sure if CR 6 creatures will help us. You could get a fey from Eberron that can cast spells of up to 5th level. Or you could get something worthless, because this is another of those "DM chooses the monster" spells. What this spell does depends entirely on DM fiat and your lack of agency means that you don't really get to feel like you own your victories or your failures. Isn't 5e summoning "fun"?


4. True Seeing (divination): This is a really good spell for enemies who do inviso and illusion shennanigans. Great spell, but slightly less great for Mystic Arcanum because it's a bit situational. Whatever you pick for Mystic Arcanum should be something you're going to want to use every day.


5. Flesh to Stone (transmutation) CON; tempting but the CON save concerns me. The petrification effect takes a long time to kick in, if at all. Other than that it's basically an all-or-nothing Con save single target Restrain spell that doesn't give you a save every round to break it. And only works on creatures made of flesh! Meh.


6. Mass Suggestion (enchantment): I already have Fear as a contro spell. Not seeing how this is an improvement. No Concentration.


8. Circle of Death (necromancy) : not feeling it, and there we go: Con Save. Still, against mobs, it's as good as fireball cast as a 3rd level spell. :smallyuk: I already have Wall of Fire.

Let's be fair here, Fireball affects a volume of ~33,500 cubic feet. Circle of Death affects ~905,000. That's a tad bigger, and it has a better damage type. That said, it's not like you can exclude inconvenient allies from that area, and it has a 500gp component, and it's still an 8d6 Con save in a 6th level slot, and it doesn't synergize with your kit, so... eh.


not sure what XGTE spells qualify

Soul Cage, Mental Prison, Scatter, and the elemental Investiture spells.

[Spiritchaser]

You guys keep recommending Mass Suggestion. Are you really in that many large scale non-combat encounters with creatures every long rest? Suggestions aren't particularly useful as a combat spell.

I haven’t played with more than a handful of DMs, and only one recently. I’d always assumed that this spell was brilliantly strong because it was both an out of combat social spell (better for sorcerers with subtle of course but still) and an effective AoE control/debuff without any friendly fire problems. Of course there are creatures it won’t work on, but that’s a reasonable limitation.

I’ve never faced a Campaign in which it wasn’t a good combat spell. Certainly I allow it to function this way with an appropriate “suggestion” In my campaigns.

But It’s entirely possible that this impression is based on a limited data set, and there are many DMs out there who regard this spell differently.

How would you treat it?

How does your DM treat it?

[Contrast]

I haven’t played with more than a handful of DMs, and only one recently. I’d always assumed that this spell was brilliantly strong because it was both an out of combat social spell (better for sorcerers with subtle of course but still) and an effective AoE control/debuff without any friendly fire problems. Of course there are creatures it won’t work on, but that’s a reasonable limitation.

I’ve never faced a Campaign in which it wasn’t a good combat spell. Certainly I allow it to function this way with an appropriate “suggestion” In my campaigns.

But It’s entirely possible that this impression is based on a limited data set, and there are many DMs out there who regard this spell differently.

How would you treat it?

How does your DM treat it?

I have tried to cast Suggestion in combat 3 times with my bard. Twice they couldn't speak the language I spoke (I assumed giants spoke Common and that elementals bound by duegar would speak Dwarvish, but unfortunately not) and once they were immune to being charmed. One of these days I'll make someone actually take a save...

[Mr Adventurer]

I have tried to cast Suggestion in combat 3 times with my bard. Twice they couldn't speak the language I spoke (I assumed giants spoke Common and that elementals bound by duegar would speak Dwarvish, but unfortunately not) and once they were immune to being charmed. One of these days I'll make someone actually take a save...

I have previously done this by opening my turn by addressing the enemy: "Do you even speak Common?!" Asking it directly like this is likely to get you an immediate response unless the DM is weird about speaking off-turn.

I also once used telepathy, the target could hear me speak and could understand me by telepathy, meeting both those requirements of the spell even though they couldn't understand my speech. YMMV.

I am not totally clear on how or whether you can use Intelligence skill checks to know information about monsters, such as their languages, but you ought to be able to try this with a Bard...

[MaxWilson]

3. Conjure Fey (conjuration) If I could up cast, yeah, but I am not sure if CR 6 creatures will help us.

Annis Hags have a good AC, decent HP, resistance to non-magical weapons, and an incredible opportunity attack. Imagine:

Annis hag hits you for 9d6+5 (36) HP of damage and grapples you if you're not Huge, then you have to spend your action escaping the grapple (DC 15) or you take another 9d6+5 at the start of the hag's next turn. She can then either just Dodge (or Dash, etc.) while hanging on for 9d6+5 auto-damage every round and dragging you around the map, or she can let go and immediately hit you for another 9d6+5 now + 9d6+5 at the start of her next turn.

Their HP are low for a monster but decent for an ~11th level PC, and you can heal them. (Due to weapon resistance any healing effectively goes twice as far, against normal weapons.)

In a way it's like the spell is Conjure Raging Barbarian except no Barbarian hits that hard.


And then something like True Seeing is a little too niche unless you're in a game where you know it'll always be useful.

Warlocks are almost helpless against creatures they can't see. Even Eldritch Blast requires you to see the target. While there are some spells like Fireball and Danse Macabre that can kill an invisible target, spending a Mystic Arcanum to cover your glaring weakness is not a terrible idea.

[RSP]

If your DM agrees to allow upcasted Warlock spells as your Arcanum, Major Image is a fantastic choice for permanent, Concentration-less illusions. In essence you can have a copy of you following around for bait, or interactions with creatures you aren’t sure of whether they’ll be friendly or not.

And that illusion can be precast so you still have a new illusion available on adventure days.

[ImproperJustice]

Soul Cage!!!

8 hour, no concentration buff with multiple applications for you to use as needed.

Excellent for intel purposes as others have stated, or advantage (I like to use mine for initiative rolls).

If you were a Chain Lock and had gift of the ever living, the 6 uses of 16hp infusions is decent.

I like it because it makes me feel like I am getting my money’s worth out of a level 6 spell.

If you think about it, in some ways it is easier to use for interrogation than asking the living...