Devil of the depths review

Blood Frenzy is a nice idea, but I'm a) questioning whether it should apply only to one target, or to any target who's taken lethal wounds in the combat
b) find the order wierd; you activate it and get a bonus based on the number of times you hurt someone last turn; you get very angry all at once. Thematically I'd say it would be better to activate it after you've caused a lethal wound (on a given target, if you're keeping that), and it automatically improves for each lethal wound you cause. May require cost increase or other downsides (such as frenzy effect) to balance that though.

Flesh Rending seems good, as does Master Predator Killing Intent.