I'm building a Vampire Lord as the father of a Dhampir PC and the player described them as an "old as f**k dude who's super suave and civil, but super evil too", and someone that's a lot like an older version of Alucard from the Castlevania series on Netflix (which I have seen, thankfully). So, I went with Investigator [Empiricist] 10 / Swashbuckler 10 and ran into a few things.
Pre-facing the questions with a simple home rule I made: The Sword Cane has the same stats as the Rapier.
So, I took the Investigator Talent called Domino Effect, the Whirlwind Attack feat, and the Lunge feat:
When the investigator uses studied strike, he uses his opponents against each other and sets himself up for his next move. Whenever he successfully deals damage to an opponent with studied strike, as a free action the investigator can apply the effects of studied combat to an opponent adjacent to the first.
When you use the full-attack action, you can give up your regular attacks and instead make one melee attack at your highest base attack bonus against each opponent within reach. You must make a separate attack roll against each opponent.
When you use the Whirlwind Attack feat, you also forfeit any bonus or extra attacks granted by other feats, spells, or abilities.
You can increase the reach of your melee attacks by 5 feet until the end of your turn by taking a –2 penalty to your AC until your next turn. You must decide to use this ability before any attacks are made.
So...
Question #1:
According to my reading of those two things, can I use the first attack from Whirlwind Attack to hit my Studied Target, use Studied Strike to do my 4d6+5 precision damage, use Domino Effect to designate the next target as my Studied Target, and then rinse and repeat for the rest of my attacks?
Question #2:
Does Whirlwind Attack work with the Lunge feat to allow me to make an attack against every enemy within 10ft of me? o_O
Question #3:
Do multiple sources of Precision Damage stack? My Vampire Lord has both the Investigator's Studied Strike and the Swashbuckler's Precise Strike, which would be a +4d6+15 precision damage...
Yes, yes and yes. Note that this damage isn't very impressive for 20th level.
@avr: Thanks for the confirmation. And that isn't all of his damage, that's just the Precision Damage itself. The normal hit would be something like 1d6+28 with Power Attack, then you add that 4d6+15... :)
Also, I'm legit not sure how Domino Effect works with Studied Combat's re-apply clause. I can only target someone with Studied Combat 1/day unless I spend a use of Inspiration in the same action I use Studied Combat.
I can use Studied Combat as a Swift Action because of Quick Study, but if I'm reading Domino Effect correctly, I could spend the Inspiration as a Free Action when I use Domino Effect's effect.
That damage is better, but the vampire lord is still going to be within a 5' step of a full attack from multiple enemies after doing the whirlwind attack, and isn't going to have taken out any significant enemies unless they were already damaged. That's a bad position to be in.
The reapply thing isn't as crystal clear as your other questions. Studied combat does specify that you spend the inspiration to reapply it 'when taking the move action to use this ability.' As a GM when you have an ability to use studied combat with a different action type (swift or free) I'd allow it, but I expect some would insist that reapplying it requires a move action.