Blood Vow

Blood Vow is a build-defining Common relic that unlocks the entire Cursed card archetype. Without it, Cursed cards carry painful penalties that make them risky to include. With Blood Vow, you get one free Cursed card per turn, letting you play powerful curse effects without consequence.

The strongest combo is Blood Vow plus Cursed Cauldron: your first curse each turn deals x1.5 damage with zero downside. Add Exile Feather to the mix and exhaust-based curse builds become an energy-generating powerhouse. Even without a full curse deck, Blood Vow makes it safe to hold onto the occasional high-value Cursed card you find along the way.

The main limitation is one free card per turn, so decks that want to spam multiple curses per turn still pay penalties on the second onward. Priority: always pick if you have any Cursed cards; it is the gateway relic for one of the strongest builds in the game.