Can a Spellcaster be "Reckless" with a Mage Slayer?

[Duke of Urrel]

The book Complete Arcane includes a feat that is highly useful to non-spellcasters: the Mage Slayer feat. Its benefit is described on page 81 as follows.


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.


I make two questionable assumptions about spellcasters who deal with enemies who have the Mage Slayer feat. Please let me know what you think of these assumptions!

Assumption 1.

If you are a spellcaster, it is reasonable (but how reasonable?) to assume that you don’t become aware that you cannot cast defensively in a game space threatened by a particular enemy until you try for the first time to cast a spell defensively in this space. Although you avoid the enemy’s attack of opportunity, as usual, you also fail your Concentration check automatically (according to the rules text above) and lose your spell without any effect. After this has happened to you once, I assume that you are fully aware that you cannot cast a spell defensively in any game space that this enemy threatens.


Assumption 2.

It is also reasonable (but how reasonable?) to assume that being unable to cast spells defensively in a game space threatened by an enemy with the Mage Slayer feat does not entail being unable to cast spells recklessly in this space. This means not bothering to use Concentration skill at all, so that you provoke an attack of opportunity from the enemy every time you start to cast a spell. However, the attack may miss, and if it does, I allow you to make a Concentration check at DC 10 plus the spell’s spell level to complete the spell. If the attack hits, I allow you to make a Concentration check at DC 10 plus the spell’s spell level plus the damage in Hit Points that you took from the attack to complete the spell.


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What do you think?

[Doctor Despair]

Assumption 1

No, the text is quite clear: for some reason, the mage is aware they cannot cast defensively while being threatened by a character with this feat. If they can see the fighter, fluff it as tactical awareness that they will be hit (he's just too quick!); if they can't see the fighter, maybe a sixth sense.



Assumption 2.

Yes, you have the option not to cast defensively. If damaged by the AoO, the use of the concentration skill to avoid losing your spell is as you described.

[Thunder999]

It's quite explicit that casters know they can't cast defensively, this is always the case (except perhaps for an invisible foe, though it's ambiguous) and is important because the feat is a lot stronger if casters don't know about it.

[Doctor Despair]

On that note... anti-caster martials really could use the help. It wouldn't be at all an unreasonable houserule to have folks not know they'll fail until they try once.

[Duke of Urrel]

No, the text is quite clear: for some reason, the mage is aware they cannot cast defensively while being threatened by a character with this feat. If they can see the fighter, fluff it as tactical awareness that they will be hit (he's just too quick!); if they can't see the fighter, maybe a sixth sense.


It's quite explicit that casters know they can't cast defensively, this is always the case (except perhaps for an invisible foe, though it's ambiguous) and is important because the feat is a lot stronger if casters don't know about it.

OK. Thanks for your responses!

This raises the question of when and how exactly you become aware, as a spellcaster, that an enemy is a Mage Slayer.

I first imagined that you might become aware of this when you came within the Mage Slayer's reach. Now I think I would rather imagine that you become aware when you first meet the Mage Slayer's gaze, which happens just before you both make initiative checks. This is how the Duel of Wills with Initiative skill works, after all.

This assumption doesn't work if the Mage Slayer is invisible or if you're unable to see them for some other reason. However, you're also not going to be casting a spell defensively if you don't even know that an enemy is there to attack you. The enemy will ready an attack to disrupt your spell, and you will have no choice but to use Concentration skill reactively to avoid losing the spell. But supposing the unseen enemy is a Mage Slayer, how do you know enough not to try to cast spells defensively after being hit the first time?

On second thought, maybe your character doesn't have to know this in-game. Only you, the player, have to know it out-of-game, in order to follow the rules appropriately.

Maybe it isn't necessary to assume that a spellcaster needs some kind of sixth sense to recognize that they're dealing with a Mage Slayer. From your perspective as a player, when you deal with a Mage Slayer, you immediately must switch from a preventive use of Concentration skill, a.k.a. defensive spellcasting, to a reactive use of Concentration skill, that is, making a Concentration check only after you fail to avoid an attack of opportunity that either hits or misses. So you, the player, have to be aware that your opponent is a Mage Slayer in order to play the game. (It would be grossly unfair if the dungeon master let you, the player, try to cast spells defensively again and again and told you again and again that you failed and lost your spell, but wouldn't tell you why.) But the spellcaster you play doesn't have to have any such awareness of game mechanics (unless they belong to the Order of the Stick). A spellcaster in mêlée combat always just tries their best to concentrate on spellcasting without getting hurt. When the spellcaster's opponent happens to be a Mage Slayer, this task just turns out to be harder and more often painful. It's not an impossible task – not if you, the player, switch from a preventive to a reactive use of Concentration skill because the dungeon master, following the rules, has just told you that you're dealing with a Mage Slayer. But the spellcasting character you play doesn't have to be aware of how you're making your Concentration checks. All the character needs to know is that their enemy is remarkably good at hitting spellcasters – which is all that a Mage Slayer is, in-game, after all.

So how about this proposal: As a player playing a spellcaster, you have to know (and the dungeon master should tell you) immediately when you're dealing with a Mage Slayer, so that you, the player, can make Concentration checks appropriately. But the character you play may identify an enemy as a Mage Slayer as such only after they try and fail either to avoid the enemy's attacks or to concentrate successfully on spells.

Thank you both for helping me to think about this more clearly!

[Vaern]

Likely, in terms of fluff, the caster might notice that the mage-slayer is keeping his eyes on the caster's spell component pouch or that he's holding a stance that's specifically intended to take advantage of openings caused by the somatic components necessary for most spells in order to interrupt or interfere with the casting of spells.
Having a sixth sense type of thing also works. If you were to just say that the player knows but the character doesn't necessarily know, though, that's not satisfying from a storytelling perspective. Then the character is simply acting differently than he normally would in-game for no apparent reason.

By RAW, however, they don't know that they can't cast defensively until they are in a threatened space. Say a wizard throws a magic missile at a fighter. No problems there. Just chucking arcane force at a walking slab of HP. Then the fighter charges him. Now that they're in melee. Now the wizard knows. The wizard realizes that the fighter's sword is at the ready, preparing to stab at his arm if he reaches for his spell component pouch. He's in danger of taking a shield to the face if he breathes a syllable of a verbal component. This fighter has dealt with wizards before. It would be a really bad idea to try counterattacking with chill touch right now. Maybe a 5-foot step back, expeditious retreat, and hope for the best would be a better strategy. Wait, this wizard only has 1st level spells prepared? What level is he? Only 6 HP... oh, yeah, never mind. He definitely dropped after that charge attack.

[Gruftzwerg]

To make Mage Slayer somewhat functional, you need extended reach like with a Spiked Chain or due to size. Otherwise the caster can always do a 5-ft step and cast then the spell. Sure, the caster can't use touch attacks anymore. But most casters don't have sole melee touch spells prepared (if at all).

If you have the extended reach and stand adjacent to the caster, he won't be able to cast so easily anymore:

a) He tries to cast in front of you. If your AoO does enough dmg, he won't be able to hit the high Concentration DC.

b) Since a 5-ft step doesn't put him out of the danger zone, the other option would be the "Withdraw" full-round-action. Here the caster can retreat from melee combat but doesn't have actions left to cast spells. The Mage Slayer can follow him to deny him further the option to cast spells carelessly.

[aglondier]

Yep...this is why our rogue wears "robes" and our mage wears costume armour...

[KillianHawkeye]

Assumption 2.

It is also reasonable (but how reasonable?) to assume that being unable to cast spells defensively in a game space threatened by an enemy with the Mage Slayer feat does not entail being unable to cast spells recklessly in this space. This means not bothering to use Concentration skill at all, so that you provoke an attack of opportunity from the enemy every time you start to cast a spell. However, the attack may miss, and if it does, I allow you to make a Concentration check at DC 10 plus the spell’s spell level to complete the spell. If the attack hits, I allow you to make a Concentration check at DC 10 plus the spell’s spell level plus the damage in Hit Points that you took from the attack to complete the spell.


From your perspective as a player, when you deal with a Mage Slayer, you immediately must switch from a preventive use of Concentration skill, a.k.a. defensive spellcasting, to a reactive use of Concentration skill, that is, making a Concentration check only after you fail to avoid an attack of opportunity that either hits or misses.

Just so you know, there's no need to make a Concentration check for an attack that misses you during spellcasting. The check is only for taking damage while casting.

[Unavenger]

This raises the question of when and how exactly you become aware, as a spellcaster, that an enemy is a Mage Slayer.

It's possible to parse the sentence as implying that it's the awareness, not just the inability, which occurs "while being threatened by a character with this feat", and honestly, to me at least that's what makes the most sense narratively as well: it's when you're in the threatened area that you understand your opponent's mage-slaying stance is of the kind which prevents you from casting defensively.

[Duke of Urrel]

Just so you know, there's no need to make a Concentration check for an attack that misses you during spellcasting. The check is only for taking damage while casting.

Your interpretation is surely the best one if we focus exclusively on the following passage.


Injury
If while trying to cast a spell you take damage, you must make a Concentration check (DC 10 + points of damage taken + the level of the spell you’re casting). If you fail the check, you lose the spell without effect. The interrupting event strikes during spellcasting if it comes between when you start and when you complete a spell (for a spell with a casting time of 1 full round or more) or if it comes in response to your casting the spell (such as an attack of opportunity provoked by the spell or a contingent attack, such as a readied action).

However, I prefer to interpret this passage in the context of the preceding one (https://www.d20srd.org/srd/magicOverview/castingSpells.htm#concentration).


To cast a spell, you must concentrate. If something interrupts your concentration while you’re casting, you must make a Concentration check or lose the spell. The more distracting the interruption and the higher the level of the spell you are trying to cast, the higher the DC is. If you fail the check, you lose the spell just as if you had cast it to no effect.

I may be house-ruling, but I prefer to judge that whenever you provoke an attack of opportunity by spellcasting, you have to make a Concentration check, even if the attack misses – because of the general rule "To cast a spell, you must concentrate." If you don't take any damage, then the Concentration DC simply becomes 10 plus the damage you took, which is zero, plus the spell's spell level.

It seems to me wrong that you should have the option of intentionally provoking an attack of opportunity – that is, intentionally opening yourself to additional injury – merely to gain a chance to avoid having to use Concentration skill.

[Duke of Urrel]

To make Mage Slayer somewhat functional, you need extended reach like with a Spiked Chain or due to size. Otherwise the caster can always do a 5-ft step and cast then the spell. Sure, the caster can't use touch attacks anymore. But most casters don't have sole melee touch spells prepared (if at all).

If you have the extended reach and stand adjacent to the caster, he won't be able to cast so easily anymore:

a) He tries to cast in front of you. If your AoO does enough dmg, he won't be able to hit the high Concentration DC.

b) Since a 5-ft step doesn't put him out of the danger zone, the other option would be the "Withdraw" full-round-action. Here the caster can retreat from melee combat but doesn't have actions left to cast spells. The Mage Slayer can follow him to deny him further the option to cast spells carelessly.

There's another way around the problem of spellcasters who try to evade Mage Slayers by taking five-foot steps. As a mêlée attacker with the Mage Slayer feat, you can ready a mêlée attack to disrupt the spellcaster's next spell and take a five-foot step as part of your readied attack (https://www.d20srd.org/srd/combat/specialInitiativeActions.htm#ready). This closes the gap between you and the spellcaster.


You can take a 5-foot step as part of your readied action, but only if you don’t otherwise move any distance during the round.

[Gruftzwerg]

There's another way around the problem of spellcasters who try to evade Mage Slayers by taking five-foot steps. As a mêlée attacker with the Mage Slayer feat, you can ready a mêlée attack to disrupt the spellcaster's next spell and take a five-foot step as part of your readied attack (https://www.d20srd.org/srd/combat/specialInitiativeActions.htm#ready). This closes the gap between you and the spellcaster.

The problem with that strategy is that you don't normally start the fight adjacent to the caster most of the times.

Assuming you win the Initiative roll, you need to walk up to the caster and thus can't take a 5-ft step with the readied action anymore. The caster can take his 5-ft step and is out of your range (unless you have extended reach as I suggested).

just as a friendly reminder: try to prevent double posts (against the rules).
You can prevent this by either:
a) editing your last post if you did forget something and no one else has posted so far
b) use the multiple quote function of the forum: right after the Reply with Quote link of a post comes the "+ symbol. You can combine multiple quotes this way. The last quote you click the regular Reply with Quote link and it directs you to your Reply page with all the marked quotes.

[KillianHawkeye]

I may be house-ruling, but I prefer to judge that whenever you provoke an attack of opportunity by spellcasting, you have to make a Concentration check, even if the attack misses – because of the general rule "To cast a spell, you must concentrate." If you don't take any damage, then the Concentration DC simply becomes 10 plus the damage you took, which is zero, plus the spell's spell level.

It seems to me wrong that you should have the option of intentionally provoking an attack of opportunity – that is, intentionally opening yourself to additional injury – merely to gain a chance to avoid having to use Concentration skill.

The Concentration DC of 10 + spell level + damage is listed as the check DC for the distraction of "Damaged during the action." No damage, no distraction, no check needed.

You can house rule that if you want, but you're definitely house ruling it. Just trying to help.

[Kish]

It seems to me wrong that you should have the option of intentionally provoking an attack of opportunity – that is, intentionally opening yourself to additional injury – merely to gain a chance to avoid having to use Concentration skill.
It appears that, for some reason, you're thinking of the nonstandard, this-carries-a-risk-of-fizzling-the-spell mode--casting defensively--as the default. But if that was actually the case, every spell cast would require a Concentration check.

[Duke of Urrel]

just as a friendly reminder: try to prevent double posts (against the rules).
You can prevent this by either:
a) editing your last post if you did forget something and no one else has posted so far
b) use the multiple quote function of the forum: right after the Reply with Quote link of a post comes the "+ symbol. You can combine multiple quotes this way. The last quote you click the regular Reply with Quote link and it directs you to your Reply page with all the marked quotes.

I was under the impression that is was okay to post twice if you were the Original Poster. I can't find that rule, so maybe I imagined it. I will be more careful in the future!

You're also right that readying a five-foot step doesn't stop a spellcaster from evading a Mage Slayer. If you're a Mage Slayer, you would be well advised to invest in Greatreach Bracers.


The Concentration DC of 10 + spell level + damage is listed as the check DC for the distraction of "Damaged during the action." No damage, no distraction, no check needed.

You can house rule that if you want, but you're definitely house ruling it. Just trying to help.

And I appreciate the help! I need confirmation to draw the line between interpreting and house ruling, and you have helped me do this. Thank you! I hereby affirm and accept that my former proposal is, in fact, a house rule only.