Can a swashbuckler parry an attack from an invisible creature, or creature they cannot see?
Breaking it down/apart (at the request of Erudaki).
Precondition: Swashbuckler class is specifically mentioned to limit the scope of "parry" to the use of the class Deed "Opportune Parry and Riposte (Ex)" (OPaR). Other forms of parry are not considered for this answer.
Precondition: swashbuckler has an AoO available (i.e. has not used all AoO they are entitled to).
Precondition: swashbuckler has a panache point to spend to use the OPaR Deed.
Precondition: invisible creature is in melee with swashbuckler as OPaR only applies to melee attacks against the swashbuckler as explicitly stated in the OPaR description.
Possible assistance: Combat Reflexes allow AoO while flat-footed. (Turns out this doesn't come into play in this specific situation.)
Possible assistance: Blind-Fight allows rerolls on misses against concealed opponents and prevents the loss of Dexterity bonus to AC against invisible opponents and prevents the +2 bonus to hit given to an invisible creature attacking you in melee. (Turns out this doesn't come into play in this specific situation.)
Looking at the Deed: "Opportune Parry and Riposte (Ex)" (OPaR)
- Requirement: 1st Level swashbuckler = granted,
- Requirement: 1 panache point to spend = granted,
- Requirement: AoO available to spend = granted, all PCs have at least one per round.
- Action: Make an attack roll AS IF IT WERE AN AoO* = granted,
(* I think this wording is used so that the AoO expended by OPaR cannot qualify for other adjustments AoOs might get from other abilities or feats the PC may possess. It does everything a normal AoO does but doesn't qualify as a prerequisite for anything.)
- The invisible creature is in melee with swashbuckler therefore is in a threatened square. (I cannot find any text in invisibility references to say the square isn't threatened, only that the swashbuckler wouldn't know which square the invisible attacker is in, or if it were in one at all... unless they pass a DC40 Perception check to pinpoint the square containing the invisible creature.)
It turns out it is irrelevant to the result whether the Perception check is passed or not, as the attacker remains invisible. If the Perception check is passed then the 5' square is know, but according to invisibility
"If a character tries to attack an invisible creature whose location he has pinpointed, he attacks normally, but the invisible creature still benefits from full concealment (and thus a 50% miss chance)."
Full Concealment = Total Concealment (Sloppy English equivalency notwithstanding)
Under Concealment, subtopic Total Concealment, last sentence
"You can’t execute an attack of opportunity against an opponent with total concealment, even if you know what square or squares the opponent occupies."
Therefore you cannot use an AoO against an invisible creature even if it is pinpointed. OPaR states:
"The swashbuckler makes an attack roll as if she were making an attack of opportunity;"
These two rules clearly answer this question with a resounding NO.
Even if that didn't end the question...
- Invisible creature attacks swashbuckler
-- Here is where English language causes issues between description and rules --
"The swashbuckler must declare the use of this ability after the creature’s attack is announced, but before its attack roll is made."
-- I contest that "announced" does not mean the invisible creature says "I stab at thee!". An invisible attack is NOT "announced" in any way other than for rules purposes, it is at best a meta-announcement. The swashbuckler has no inkling IF an attack is coming, let alone WHEN. It makes no logical sense to be able to block something you cannot see... unless you know... magic. However OPaR is (Ex) not (Sp) not even (Su) so it is NOT magic.
"Extraordinary abilities are non-magical. They are, however, not something that just anyone can do or even learn to do without extensive training. Effects or areas that suppress or negate magic have no effect on extraordinary abilities."
If the swashbuckler cannot know when an attack is coming before it hits them, and potentially never knows if an attack misses them, then they have no cue to declare anything. OPaR cannot even be triggered in this situation!
Yes, he can...
First of all the invisible condition is an effect that you GAIN not a malus that you APPLY to someone else:
Invisible: Invisible creatures are visually undetectable. An invisible creature gains a +2 bonus on attack rolls against a sighted opponent, and ignores its opponent’s Dexterity bonus to AC (if any). See the invisibility special ability.
As we can see the condition itself does two things: 1) you gain an attack bonus and 2) your target has no dex bonus to AC... the target is not flat-footed. Flat-footed is another condition.
Other than this the invisibility special ability says:
- While they can’t be seen, invisible creatures can be heard, smelled, or felt
- Invisibility makes a creature undetectable by vision, including darkvision
- Not immune to critical hits but immune to extra damage (ranger favored enemy, sneak attack...swashbuckler precision damage too i think)
- If the invisible creature is adjacent to the attacked creature it gains total concealment otherwise the attacked creature need to find a way to pinpoint the invisible creature
- Many other things... (like invisible creature leaves tracks, displace liquids and so on)
Now, going to the swashbuckler parry/reposte:
Opportune Parry and Riposte (Ex): At 1st level, when an opponent makes a melee attack against the swashbuckler, she can spend 1 panache point and expend a use of an attack of opportunity to attempt to parry that attack. The swashbuckler makes an attack roll as if she were making an attack of opportunity. [...]
Now we can see different things:
- Opportune Parry and Riposte is not an attack of opportunity. It costs a use of an attack of opportunity and you attack as if it is an attack of opportunity..because it isn't.(i hope this part is clear enough).
- Nothing specifies conditions about the state of the attacker. This means that we don't know if it's required to see the attacker or to hear the attacker and so on.
And that's it.
Nothing prevents actually to use opportune parry and riposte versus an invisible attacker...and you do not need those two feats at all. You do not need feats at all since when you are fighting an invisible enemy you are not flat footed (so combat reflexes isn't needed) and blind fight gives you more AC (since you retain DEX to armor) but that's it.
What happens if your GM treat opportune parry and riposte as a real attack of opportunity? Well...in this case you can not make opportune parry and riposte since you can not make attack of opportunity to an opponent with total concealment :
[...] You can’t execute an attack of opportunity against an opponent with total concealment, even if you know what square or squares the opponent occupies.
So your only chances in this case are:
- see invisibility (in some way)
- remove your dependency from eyesight (like echolocation for example)
- Greater Blind-Fight (or similar effect that decreases or removes the total concealment from your opponent)
I hope it's enough, good game!