Can talents of the samurai be used after the attack overcame the samurai?
The rulebook doesn't specify anything about this at the talents and the only effects the overcome seems to have is that
Case 3: If the total is GREATER THAN your Kiai value, you are overcome by raiders: Immediately remove one village Barricade.
and in the next round
Important: If your Samurai meeple is already past your Kiai value (i.e. on the flame), then you MUST PASS.
For some talents it would make sense that it can still be used as they are passive looking (at least to me). For example if Gorobei is overcome, he should(?) still be able to ignore the penalty on a Raider with an even value.
The real, specific question is: after Kikuchiyo becomes overcome by an attack, can he still use his talent and choose to fight another opponent even though he is already overcome?