Invisibility and ready action

[Trainz]

Since it is very hard to pin-point an invisible target, is it possible to ready an action to attack the invisible foe when he will attack you ?

If he attacks you, can you assume that you pin-pointed him in order to make your readied attack ?

If an ally does the same thing, and even though the invisible foe attacks you, can your ally attack it if it is in his reach ? Or could he make a 5 ' step to be in reach ?

I'm asking this, because we had an encounter with a will o' wisp that nearly TPK'ed us and we are EL 8. Under those circumstances, and if my above question's answers are negative, let me tell you the W o' W'sps CR is way too low...


Trainz

 

[Someone]

Not having here my books and being lazy to check the SRD, I´d say:

a) Yes, as long you know you´re being attacked (the invisible enemy becomes visible or, if Improved Invisible, it hits you)

b) Yes, if a invisible enemy hits you you automatically know in what square he is unless (IIRC) he´s more than 5 feet away from you. Note that the 50% miss chance still applies.

c1) Not really. Note that your ally actually doesn´t have a chance to know when the invisible foe is attacking, so he have to ready an action to attack "Just after my buddy is hit" Not the same thing, since readied actions go before the action that triggered it, and note that your friend have no idea of where the enemy is unlike you (ok, you can tell him)
c2) Sure, unless he has moved before readying the attack.

 

[daemonslye]

There may be a few items to consider:

1. Will-O'-Wisps do not normally engage in combat.

MMp.183 COMBAT:
"Will-o'-wisps usually avoid combat."
"They prefer to confuse and bewilder adventurers, luring them
into morasses or other hazardous places."

2. They feed on "panic, horror, and death". They usual
MO of the creature would be to lead your party into a
quicksand trap, the like, or another encounter and
feed off of the resulting terror.

3. Though the creature has "Natural Invisibility", it only
assumes this form when "startled or frightened".
It would be easy to assume here that this mode
would be used primarily for escape.

4. Interestingly, though the WW and the Invisible Stalker
share the same trait, for the WW it is "extraordinary"
(EX) and for the IS it is "supernatural" (SU). This generally
makes the WW's natural invisibility superior.

5. Given the above, I would rule that a WW that is being
attacked, takes damage, and does not leave combat
(due to environmental reasons, allegiances, protecting
it's "nest" or other) and continues to attack unto the
death requires a modification of CR. However, I won't
hazard a guess on this, ask your DM; He knows what
to factor in here.

6. WWs are a fine example of why it is great to have
see invisibile and magic missile. One or
two pops should be all it takes. Otherwise, you may
want to consider the "all-out-run" option.

...I think the rules regarding invisibility and
combat have been reviewed here many times.

~D

 

[Saeviomagy]

You can ready the attack.
Your DM should inform you of the square that the attack is originating from (assuming there is no reach involved)
Your attack will then have to cope with miss chances as usual.