Aetherflux Reservoir [Kaladesh Prerelease Promos]Set: Kaladesh Prerelease Promos Type: Artifact Rarity: Rare Cost: {4} Whenever you cast a spell, you gain 1 life for each spell you've cast this turn. Pay 50 life: Aetherflux Reservoir deals 50 damage to any target. While most power is used for ordinary, everyday tasks, one shouldn't underestimate its potential for the extraordinary.