Concentration check on a supernatural ability?

Question

Another question brought up a scenario where a crimson assassin used the supernatural ability prayer attack to deliver a coup-de-grace to a PC. The question was about how to prevent the coup-de-grace.

Prayer attack specifically notes that it requires concentration, but there are no rules that I can find for concentration checks on a supernatural ability. If it requires a concentration check, a fascinated creature's allies can save him by dealing damage to the assassin. This seems like a clear design reason to require a check. Do the rules support this interpretation?

Prayer attack At 2nd level, a Crimson assassin learns her signature assassination style. To initiate a prayer attack, she holds her sawtooth sabre (or sabres) out, point down, and weaves the blade in the air. She must be within 30 feet of and visible to her victim. Beginning a prayer attack is a standard action, and causes her victim to be fascinated by her unless he makes a Will save (DC 10 + the Crimson assassin’s class level + her Charisma modifier—if she’s wielding two sawtooth sabres, this DC gains a +2 bonus). She can maintain the fascination effect by concentrating. The victim may attempt a new save to escape fascination each time a threat (other than the fascinating assassin) appears. At any point after 3 rounds, she may make a coup de grace attack against the target, provided the target is still fascinated. Activating or concentrating on maintaining a prayer attack does not provoke an attack of opportunity.

Can this concentration be interrupted by taking damage? It seems like it would be hard to concentrate while getting smashed in the face, but the rules don't seem to cover this.

The rules for concentration checks specifically talk about "casting a spell." There are rules for losing concentration on a spell due to damage while casting, but this is not a spell.

There are three definitions of supernatural ability. From the magic page:

Supernatural Abilities (Su)

These can’t be disrupted in combat and generally don’t provoke attacks of opportunity. They aren’t subject to spell resistance, counterspells, or dispel magic, and don’t function in antimagic areas.

From the special abilities page:

Supernatural Abilities (Su)

Supernatural abilities are magical but not spell-like. Supernatural abilities are not subject to spell resistance and do not function in areas where magic is suppressed or negated (such as an antimagic field). A supernatural ability’s effect cannot be dispelled and is not subject to counterspells.

From the combat page:

Supernatural Abilities (Su)

Using a supernatural ability is usually a standard action (unless defined otherwise by the ability’s description). Its use cannot be disrupted, does not require concentration, and does not provoke attacks of opportunity.

These are general rules, and seem to mostly be a general description. Specific rules overrule general rules, and this supernatural ability specifically requires concentration. RAW, Does this mean it "can be disrupted in combat?"

Answer 1

So there are two different issues to concentrating:

1. Concentration can usually be disrupted.

2. Concentration takes your attention, read, your action.

Concentrating on a magical effect is a standard action. While you are concentrating, you cannot be doing other standard actions (usually).

So as a supernatural ability, the prayer attack cannot be disrupted. You do not need to make Concentration checks (or, equivalent, you automatically pass them, since it’s impossible to be disrupted). But you still do have to pay attention to what you’re doing. So you have to spend standard actions each round concentrating on the effect to keep it going.

In effect, the prayer attack has a duration of “Concentration” which is distinct from the idea of concentrating on something to avoid disruption.

Answer 2

If the ability says it requires concentration, then it does.

Supernatural abilities normally do not require concentration checks, but there are examples of abilities that do require concentration even being (Su), such as Emotional Bond (Psychic class) and Eternal Whispers (Kineticist class).

However, since this ability did not replace the more general rule saying that "supernatural abilities cannot be disrupted", even if they fail their concentration check, the ability would still go off, as per rules as written. You will notice that Eternal Whispers does say that the effect is disrupted if you take damage while concentrating.

There is no way to know the rules as intended here, since these cases are few and far apart. But if i had to guess, requiring concentration here simply means that you cannot use your Standard Actions for anything else other than to maintain concentration (example: You cannot cast a spell while concentrating).

This FAQ item also suggests that, even if the ability does not have a listed spell level (required for the concentration DC), you calculate it's DC based on the character's level and highest spell level she can cast when she obtains the spell. Here, the ability is obtained at 2nd level, and the highest spell level the character can cast are 1st level spells, so the concentration DC for being injuried would be 11 + damage taken.

Cleric domains, sorcerer bloodlines, wizard schools, and certain other class features give spell-like abilities that aren't based on spells. What's the effective spell level for these abilities?

The effective spell level for these spell-like abilities is equal to the highest-level spell that a character of that class could normally cast at the level the ability is gained.

For example, a 1st-level elemental bloodline sorcerer has elemental ray as a spell-like ability. Because a sorcerer 1's highest-level spell available is 1st, that spell-like ability counts as a 1st-level spell. A 9th-level elemental bloodline sorcerer has elemental blast as a spell-like ability. Because a sorcerer 9's highest-level spell available is 4th, that spell-like ability counts as a 4th-level spell.

Yes, the FAQ talks about spell-like abilities, but the intent here seems to be to cover areas that were left vague by the system.

The question remaining is: Should the ability be disrupted if the characters fails the concentration check? Everything suggests that the answer is No.

Answer 3

Any action or condition that requires a concentration check will disrupt the fascination and prevent the prayer attack's coup de grace, because the only relevant rule here is the class's ability description, which is very specific:

She can maintain the fascination effect by concentrating.

That means that she must maintain it (or it is lost) and that concentration is required to do so. This is a very specific rule that applies solely to the crimson assassin's Prayer Attack supernatural ability. It in no way means that other supernatural abilities either require a concentration check or can be disrupted, unless they say so, because the general rule is as you stated:

Supernatural Abilities (Su): These can’t be disrupted in combat and generally don’t provoke attacks of opportunity. They aren’t subject to spell resistance, counterspells, or dispel magic, and don’t function in antimagic areas.

Edit: apologies, I of course meant "...will disrupt the fascination and prevent the prayer attack's coup de grace if the concentration check is failed, because..."

Answer 4

The Listed Concentration is a Duration

The Spell Duration section says:

Concentration

The spell lasts as long as you concentrate on it. Concentrating to maintain a spell is a standard action that does not provoke attacks of opportunity. Anything that could break your concentration when casting a spell can also break your concentration while you’re maintaining one, causing the spell to end. See concentration.

You can’t cast a spell while concentrating on another one. Some spells last for a short time after you cease concentrating.

Once you stop concentrating, the effect ends, obviously. Since normally Supernatural Abilities require no concentration, then when one does, that concentration should be disruptable as normal, by anything that could disrupt an equivalent spell. The hard part here is that there's no caster level, spell level or associated casting ability.

Or is there?

At 2nd level... a Will save (DC 10 + the Crimson assassin’s class level + her Charisma modifier...

This FAQ entry linked to by @ShadowKras shows that for spell-like abilities, the spell level is the same as the highest level spell that the class could cast when it gains the ability.

With a very slight extrapolation, we can come up with useful and correct numbers for the Concentration DC calculations. A Crimson Assassin can cast 1st level spells at 2nd level, when it gains the ability, so the ability is equivalent to a 1st level spell. The Crimson Assassin's casting Stat is Charisma, and it has a Caster Level equal to its Class Level.

So there's a complete set of the numbers needed to set-up the Concentration check DCs for the Assassin to make in distracting circumstances to continue concentrating on its ability.