Vigil for the Lost

A lifegain engine that prices its own payoff. The trigger fires for free whenever a creature you control dies, but the gain is locked behind an open-ended payment, so the enchantment converts mana you weren't spending elsewhere into life rather than handing it out automatically. That structure carries the whole card: when your board is collapsing and you're tapped out, it does nothing, because the life only arrives if the mana is there to buy it. It rewards the turns where a creature is dying and surplus mana is sitting around, a narrower window than the unconditional reading of "gain life when something dies" suggests. The card sits among the token-and-attrition white sinks that ask a deck to flood the board with bodies and then drain the leftover mana into a resource the deck actually needs, turning expendable creatures and excess lands into a slow life cushion. The catch is that the conversion rate is one-to-one and the floor on each trigger is zero, so it is built for grindy, mana-rich shells where small creatures die in volume and the late game has nothing better to do with floating mana. Outside that context the trigger is cosmetic; inside it, the enchantment quietly turns a sacrificed token and four open lands into four life, over and over, for as long as the board keeps churning.