You can never have to much critical chance.
Tanya and Overkill only proc on critical.

Unique Skill:
Chance to gain 5 kill points in EvE/PvP/Boss for spending tokens and stamina

Attacking a target consume 1 kill point and gives 100% critical chance.

Absorbing token will reduce the incoming damage by x% and bonus damage by x%(Ace)

Not my idea just tweeked Salvatore skill a bit!