Bloodlust (Rare relic): overkill damage you deal is stored, and at the start of your next combat you gain that much Vigor, up to 20. Source
Bloodlust gave the end of each battle real tension and tradeoffs. It generated meaningful choices.
rrenaud, after the run
Each bar is what that fight stored, out of 20, and is the Vigor the next fight opened with. Click a bar to jump to the fight.
Each fight has a screenshot at the start of turn 1 and at the end. → flips through all of them.