Invisible attacker with mage slayer

[Crake]

So a character of mine, who focuses pretty much entirely on not being seen, not actually via invisibility but rather through hide in plain sight and a ridiculous hide check (with a level in exemplar, so she can take 10 on it as well, guaranteeing a 47 on her hide check, or 27 when attacking, so people without ranks or some kind of good bonus to spot cant see her even when she punches them right in the face) is considering getting the mage slayer feat.

Now, at first I just thought that this would allow her to attack casting mages even when they try to cast defensively, but upon re-reading the way the feat works, it seems to put things into a state of strange limbo. Casters she threatens will automatically fail their concentration checks to cast when she is threatening them, yet she is not visibly threatening them, and supposedly they would know that this is going to happen even though they can't see her.

My natural instinct (since I'm the DM, and this is for an NPC) is to say that casters will simply provoke and she will get an attack of opportunity whenever she invisibly threatens them while they cast, because it seems to be the only logical step forward, but I don't want to set a bad precedence, so I ask you guys: Is there any way to reconcile these two ideas? Is there a way for the mage slayer feat to function with a hidden attacker in such a way that would actually make sense?

[Kelb_Panthera]

Simple answer: why would they cast defensively if they didn't know they were threatened?

In any case, I'd house-rule that they don't automatically know their attempt to cast defensively will fail if they're unaware of the mage-slayer but the feat otherwise functions as written.

[Crake]

Simple answer: why would they cast defensively if they didn't know they were threatened?

In any case, I'd house-rule that they don't automatically know their attempt to cast defensively will fail if they're unaware of the mage-slayer but the feat otherwise functions as written.

Generally speaking because there are other people about who are threatening them, also because, at least after the first hit, they are aware of an invisible attacker somewhere, or, depending on the enemy, they may be aware that the group has someone capable of striking, unseen from the shadows, so casting defensively at all times would only make sense, especially at the level we're playing at, where it's almost impossible to fail a defensive casting check.

I've always interpreted mage slayer in a way that says you're so harrowing to spellcasters that it requires too much attention to prevent an attack of opportunity to actually cast defensively, but how could a spellcaster know you're being so harrowing if they can't even see you?

[Pleh]

I come to the following ruling:

RAW on hide in plain sight states you can hide while being observed, while RAW for the hide skill says that for hiding while being observed, the creatures that were observing you still have some idea of where you must have gone. Finally, RAW for mage slayer says that casters you threaten cannot cast defensively and automatically fail their concentration check to do so, but that they are also aware of their inability to cast defensively.

I always saw hide in plain sight to work a bit like assassin's Creed. It's not that they can't see you, since you're in plain sight. It's that they don't notice you as you look like an unimportant bystander.

With that, I would rule two possible scenarios:

1. The notice you before you hide in plain sight. They at least notice your absence and then definitely notice that someone is disrupting their Defensive casting. This would be ruled at my table as giving them an enormous circumstance bonus to their future attempts to notice you, since they have both a reason to look for you as well as a general area you could possibly be occupying.

2. They did not notice you before combat began, but they notice something is threatening them to prevent defensive casting. This grants a less substantial circumstance bonus to their spot check since they don't know what they're looking for, even though they might have good reason to believe it must be in a square adjacent to themselves.

A couple of supplemental strategies to counter act these circumstances bonuses: using a reach weapon to increase the area you could threaten with and having a friend visibly threaten the caster to make it seem that your friend is using mage slayer.

[Kaje]

Why would "being harrowing" reduce one's CL by 4?

[supersonic29]

If you're strict to RAW then I think you have to deliver the threatened party a vague "if you cast defensively, you will fail your check" info-box. Immersion breaking, but it says they know they will automatically fail if they will. That being said, common sense is banging at your door telling you to have them fail the check without knowing why. If you'd have them receive the AoO without the player knowing, why would they know about this mage-slayer's threat? It certainly seems wrong to day that the mage-slayer feat grants its victims some sort of divination to its own fault. I know where you're coming from as far as feeling that this is a harsh ruling when an NPC is the one with the feat, but from that angle you could always go with something like what Pleh said and have this only occur on absolute surprise and not if they saw the NPC and then lost sight of them.

[Crake]

I come to the following ruling:

RAW on hide in plain sight states you can hide while being observed, while RAW for the hide skill says that for hiding while being observed, the creatures that were observing you still have some idea of where you must have gone. Finally, RAW for mage slayer says that casters you threaten cannot cast defensively and automatically fail their concentration check to do so, but that they are also aware of their inability to cast defensively.

I always saw hide in plain sight to work a bit like assassin's Creed. It's not that they can't see you, since you're in plain sight. It's that they don't notice you as you look like an unimportant bystander.

With that, I would rule two possible scenarios:

1. The notice you before you hide in plain sight. They at least notice your absence and then definitely notice that someone is disrupting their Defensive casting. This would be ruled at my table as giving them an enormous circumstance bonus to their future attempts to notice you, since they have both a reason to look for you as well as a general area you could possibly be occupying.

2. They did not notice you before combat began, but they notice something is threatening them to prevent defensive casting. This grants a less substantial circumstance bonus to their spot check since they don't know what they're looking for, even though they might have good reason to believe it must be in a square adjacent to themselves.

A couple of supplemental strategies to counter act these circumstances bonuses: using a reach weapon to increase the area you could threaten with and having a friend visibly threaten the caster to make it seem that your friend is using mage slayer.

Two quick points, firstly the hide skill simply states that you cannot hide while being observed without a distraction, hide in plain sight obviates that requirement. Secondly hide in plain sight is a supernatural ability, it is magical, and literally, in an empty room, devoid of any other distractions, you could hide right in front of someone and they would not be able to see you, at least with the version in use currently (the shadowdancer version). The ranger version, for example, is Ex, but that's more like using a gilly suit in a forest, and specifically only functions in natural terrain, combining with the camoflage ability to allow you to hide while being observed without any cover or concealment. What you described is literally just the normal hide skill, there already exists rules for hiding in a crowd just like in assassin's creed, it has nothing to do with hide in plain sight.

Regarding your scenarios, the character is quite literally always moving around hidden, hiding in the shadows of the party members, and as for circumstantial bonuses to spot, that seems pretty ludicrous. If you want another chance to spot, that's what actively spotting as a move action is for. There's already enough things making hiding a pain in the ass (namely that every time you move or act, or do anything really, you need to roll another hide/move silently check), so giving opponents circumstantial bonuses out of nowhere, yeah, not at my table. Do you apply these bonuses against people who are invisible as well? I somehow doubt it.

None of this explains how or why they "sense they cannot defensively cast" against someone they cannot percieve in the slightest though.


Why would "being harrowing" reduce one's CL by 4?

How would you explain reducing one's CL by 4, beyond balance reasons? The fluff of the feat is "You have studied the ways and weaknesses of spellcasters and can time your attacks and defenses against them expertly." Which basically means you know how to harass them in such a way that they cannot meaningfully cast defensively, but if it's a matter of perception, they see you attacking them, and have to pull away, breaking their concentration, then why would they do that against someone they cannot see?


If you're strict to RAW then I think you have to deliver the threatened party a vague "if you cast defensively, you will fail your check" info-box. Immersion breaking, but it says they know they will automatically fail if they will. That being said, common sense is banging at your door telling you to have them fail the check without knowing why. If you'd have them receive the AoO without the player knowing, why would they know about this mage-slayer's threat? It certainly seems wrong to day that the mage-slayer feat grants its victims some sort of divination to its own fault. I know where you're coming from as far as feeling that this is a harsh ruling when an NPC is the one with the feat, but from that angle you could always go with something like what Pleh said and have this only occur on absolute surprise and not if they saw the NPC and then lost sight of them.

I am more than happy to not go by strict raw, as the answer is perfectly clear how it would function by strict raw: You threaten them, they cannot cast defensively and are aware of such. The point of contention for me is this: Even if they are aware that someone with the mage slayer feat is roaming about, how will they ever be aware that they are actually being threatened by that person? By raw, any spellcaster would automatically know they are being threatened by someone with the mage slayer feat, even when they have absolutely no means of knowing that whatsoever. This is different from what others have been suggesting, because it's the difference between knowing someone is in the room, and knowing someone is right next to you. It just makes no sense.

[supersonic29]

I am more than happy to not go by strict raw, as the answer is perfectly clear how it would function by strict raw: You threaten them, they cannot cast defensively and are aware of such. The point of contention for me is this: Even if they are aware that someone with the mage slayer feat is roaming about, how will they ever be aware that they are actually being threatened by that person? By raw, any spellcaster would automatically know they are being threatened by someone with the mage slayer feat, even when they have absolutely no means of knowing that whatsoever. This is different from what others have been suggesting, because it's the difference between knowing someone is in the room, and knowing someone is right next to you. It just makes no sense.

Oh absolutely, by all means of reason the mage should be disadvantageously unaware. Any form of compromise would come from worry for balance rather than reason. Probably not an issue, but I figured it's an angle to think along since mage slayer is a pretty good feat and that would technically be a buff from the RAW, which I'm generally wary about as a DM.

[Pleh]

hide in plain sight is a supernatural ability, it is magical, and literally, in an empty room, devoid of any other distractions, you could hide right in front of someone and they would not be able to see you, at least with the version in use currently (the shadowdancer version). The ranger version, for example, is Ex, but that's more like using a gilly suit in a forest, and specifically only functions in natural terrain, combining with the camoflage ability to allow you to hide while being observed without any cover or concealment. What you described is literally just the normal hide skill, there already exists rules for hiding in a crowd just like in assassin's creed, it has nothing to do with hide in plain sight.

Point taken, but let's get back on track. This is kind of a minor issue.


Regarding your scenarios, the character is quite literally always moving around hidden, hiding in the shadows of the party members, and as for circumstantial bonuses to spot, that seems pretty ludicrous. If you want another chance to spot, that's what actively spotting as a move action is for. There's already enough things making hiding a pain in the ass (namely that every time you move or act, or do anything really, you need to roll another hide/move silently check), so giving opponents circumstantial bonuses out of nowhere, yeah, not at my table. Do you apply these bonuses against people who are invisible as well? I somehow doubt it.

1. Circumstance bonuses are something the DM is supposed to apply in any situation that merits them. Just basic D&D 101. If it's unfair, it's just because the rules were written unfairly. If the rules were written unfairly, it's probably because the authors thought that what you are trying to accomplish ought to be more intrinsically difficult than other potential strategies.

2. I wasn't meaning to give the caster a free spot check without taking an action, so I'm sorry if I miscommunicated that. Just that they would get a bonus to making a spot check to try to find you and that it wouldn't be unreasonable for the caster to try to use some area based spells, like cones or novas, to hit the general area you're likely to occupy. Really, this comes down to how smart the DM is planning to play the NPC. Will they use AI logic, where I can't attack what I can't see, or are they using competitive enemies who use every possible advantage, like anticipating where unseen enemies will try to pop up next?

3. If someone turned invisible right in front of your eyes during combat, whether by magic or extraordinary hiding skills, you still could attempt to attack the space they were in or the space you think they would have moved into. It's hardly out of left field to expect their previous knowledge of where you used to be to help give them bonuses to finding your later. So, yes, I would apply these same rules to invisible characters. If that seems unfair, see also point 1.


None of this explains how or why they "sense they cannot defensively cast" against someone they cannot percieve in the slightest though.

This is where I would caution against reading too far into the fluff explanation in Mage Slayer. Remember that fluff is just fluff and mechanics are mechanics. Many books actively encourage fluff reinterpretation of how feats work for a specific character or campaign setting. Changing the effects of mechanics, however, changes the balance of the game and comes down to a strict DM decision.

It's easy and harmless to come up with any number of fluff reasons besides "harrowing" to explain how the mechanics of the feat work. Use some imagination. It may be more difficult to justify granting a more powerful version of a feat to your character just because the rules are inconvenient to your strategy.

A few that come to mind are:

"The caster knows they cannot cast defensively, but they do not know why."
Once again, if the DM is playing the NPC like they would their own PC character, after having been attacked by the unseen assailant, they would have a pretty good educated guess about what's happening, even if they still cannot pin point their adversary.

"The caster might mistake the feat's effect for an illusory or enchantment effect that an enemy caster has placed upon them."
Probably would only take a quick spellcraft or Detect Magic type deal to dismiss the erroneous interpretation, but it still could explain how the feat works as intended without directly compromising your stealth.

"The caster knows one of his adversaries is using mage slayer, but he cannot be sure which one."
This is one I recommended, but DOES on some level require your allies to be playing along with the charade for full effectiveness.


The point of contention for me is this: Even if they are aware that someone with the mage slayer feat is roaming about, how will they ever be aware that they are actually being threatened by that person? By raw, any spellcaster would automatically know they are being threatened by someone with the mage slayer feat, even when they have absolutely no means of knowing that whatsoever.

Let's take a closer look at Mage Slayer:

Benefit
You gain a +1 bonus on Will saving throws. Spellcasters you threaten may not cast defensively (they automatically fail their Concentration checks to do so), but they are aware that they cannot cast defensively while being threatened by a character with this feat.

It doesn't actually say they are aware they are being threatened by a character with this feat. It says they are aware that they cannot cast defensively for as long as they are threatened by a character with this feat. What the caster knows is that they cannot cast defensively, not the reason why they cannot cast defensively (nor even are they being given the fact that they are being threatened).

They don't have to even be aware that another person is in the room. Like I mentioned earlier, it could be a ranged attack from an enemy caster for all they know. It would be disturbing, put them on high alert, and they would likely start using divination magic and/or spot checks to figure out where the effect was coming from, but the feat by itself would not tell the caster what was preventing them from casting defensively.

[Segev]

"Casting defensively" is clearly different, in some way, from "casting normally." It requires a Concentration check, and it's something you can fail to do, and know you've failed to do it.

I suspect that this falls into the same category as an invisible flanker. Flanking gives a +2 bonus to hit, presumably due to the increased distraction of having to defend against two sides and not being able to keep eyes on both. If somebody is invisible and hasn't attacked (thus not broken invisibility), he still seems to provide a flanking bonus to his buddy. Does the defender know he's being flanked? How is the attack bonus granted if the flanker is not known to the defender?

Either there's an "aura of menace" or "killing intent" or something that is just sensed by the target, or his attempt to cast defensively is disrupted by "something" before he even gets it off the ground (just as the flanked character's defense is disrupted by non-attack interference from the invisible flanker), so our mage knows as soon as he begins to try to cast defensively that it won't work, and that he's going to have to cast normally or abort.

He may not know WHY his efforts to focus on defense are failing. But something is preventing him from concentrating. Maybe it's a sense of unease. Maybe it's that trying gets him a light, non-damaging smack or distracting noise. Maybe the effort of concentrating on defense tells him something isn't right and that he's NOT going to be able to avoid attacks if he casts, no matter how hard he tries.

He doesn't know you're there, but he knows something's wrong.

[Crake]

"Casting defensively" is clearly different, in some way, from "casting normally." It requires a Concentration check, and it's something you can fail to do, and know you've failed to do it.

I suspect that this falls into the same category as an invisible flanker. Flanking gives a +2 bonus to hit, presumably due to the increased distraction of having to defend against two sides and not being able to keep eyes on both. If somebody is invisible and hasn't attacked (thus not broken invisibility), he still seems to provide a flanking bonus to his buddy. Does the defender know he's being flanked? How is the attack bonus granted if the flanker is not known to the defender?

Either there's an "aura of menace" or "killing intent" or something that is just sensed by the target, or his attempt to cast defensively is disrupted by "something" before he even gets it off the ground (just as the flanked character's defense is disrupted by non-attack interference from the invisible flanker), so our mage knows as soon as he begins to try to cast defensively that it won't work, and that he's going to have to cast normally or abort.

He may not know WHY his efforts to focus on defense are failing. But something is preventing him from concentrating. Maybe it's a sense of unease. Maybe it's that trying gets him a light, non-damaging smack or distracting noise. Maybe the effort of concentrating on defense tells him something isn't right and that he's NOT going to be able to avoid attacks if he casts, no matter how hard he tries.

He doesn't know you're there, but he knows something's wrong.

In our games, invisible or otherwise hidden attackers do not provide flanking, as they already have a +2 bonus to attacks from being invisible, so unfortunately that logic doesn't really apply. And if the feat only serves to alert enemies when you are adjacent, that seems to make it a pretty horrible feat for someone trying to stay hidden and keep their location obfuscated.

[Thurbane]

I think I asked this exact question in a RAW thread once...from memory, the answer along the lines of "The caster knows he can't cast defensively, but he's not really sure why".

[Pleh]

And if the feat only serves to alert enemies when you are adjacent, that seems to make it a pretty horrible feat for someone trying to stay hidden and keep their location obfuscated.

Once again, knowing that SOMETHING is blocking his ability to cast defensively doesn't tell him that there is a creature adjacent to him. It's a reason to investigate, not automatic knowledge of an invisible attacker using mage slayer.

Honestly, attacking the caster is a much better indication that there is a creature threatening him.

[Segev]

In our games, invisible or otherwise hidden attackers do not provide flanking, as they already have a +2 bonus to attacks from being invisible, so unfortunately that logic doesn't really apply. And if the feat only serves to alert enemies when you are adjacent, that seems to make it a pretty horrible feat for someone trying to stay hidden and keep their location obfuscated.

I believe that is a house rule, but since you asked for your game specifically, that does become meaningful.

That said, the feat doesn't "just" alert enemies that you're adjacent. It also still makes them unable to cast defensively. And, if they don't know why they can't, they don't know you're adjacent. And even if they do guess "it must be some jerk with Mage Slayer standing next to me," they don't know where you are. Heck, if you're threatening them with a reach weapon, you needn't be adjacent!

[Crake]

Once again, knowing that SOMETHING is blocking his ability to cast defensively doesn't tell him that there is a creature adjacent to him. It's a reason to investigate, not automatic knowledge of an invisible attacker using mage slayer.

Honestly, attacking the caster is a much better indication that there is a creature threatening him.


I believe that is a house rule, but since you asked for your game specifically, that does become meaningful.

That said, the feat doesn't "just" alert enemies that you're adjacent. It also still makes them unable to cast defensively. And, if they don't know why they can't, they don't know you're adjacent. And even if they do guess "it must be some jerk with Mage Slayer standing next to me," they don't know where you are. Heck, if you're threatening them with a reach weapon, you needn't be adjacent!

Except attacking the caster is something you have control over, you can reveal your presence at your own convenience, dealing a decisive blow to try and interrupt an enemy caster at a key moment, rather than having them somehow sense they're unable to cast defensively. Note that whether or not they know the reason is irrelevant, the fact that they are now alerted to some kind of presence or force which puts them on high alert and causes them to want to investigate is pretty terrible, especially when enemies are capable of casting things like blasphemy which allows them to hit the invisible attacker without even knowing where they are, as long as they're close. Also, the fact that they can move away and feel the sudden presence preventing them from casting defensively disappear is quite telling.

And yeah, we're all aware that the whole "Don't provide flanking while invisible" thing is a houserule, but it's just one of those things that doesn't particularly make sense in any of our minds. Which is the same case with this feat and the mage being unable to cast defensively. I might just avoid the whole thing and give the NPC a different feat, as this one is causing too much of a headache.

[Segev]

Well, if you have a house rule about flanking, just make a house rule about invisible mage-slayers. It would make sense that they don't know better until they're attacked. If you're worried that opens them up too much, give them the ability to auto-negate the AoO by aborting the spell. Choose whether both spell and AoO are expended, or neither are expended, to suit your balance tastes.

[Pleh]

Except attacking the caster is something you have control over, you can reveal your presence at your own convenience, dealing a decisive blow to try and interrupt an enemy caster at a key moment, rather than having them somehow sense they're unable to cast defensively. Note that whether or not they know the reason is irrelevant, the fact that they are now alerted to some kind of presence or force which puts them on high alert and causes them to want to investigate is pretty terrible, especially when enemies are capable of casting things like blasphemy which allows them to hit the invisible attacker without even knowing where they are, as long as they're close. Also, the fact that they can move away and feel the sudden presence preventing them from casting defensively disappear is quite telling.

And yeah, we're all aware that the whole "Don't provide flanking while invisible" thing is a houserule, but it's just one of those things that doesn't particularly make sense in any of our minds. Which is the same case with this feat and the mage being unable to cast defensively. I might just avoid the whole thing and give the NPC a different feat, as this one is causing too much of a headache.

How long do you want to breathe awkwardly on the caster's neck before you shank em? If you need a few rounds before making your attack, just hang out just outside range until you're ready to 5ft step and stabby stab. They'll be alerted that something is off when you move, but it's still a surprise round and they can't do anything that they could if you were only invisible. Not really that different.