Kozilek's Translator

The tension here is structural: Eldrazi want colorless mana, but black is the color least equipped to make it. This Drone resolves the mismatch by converting black's deepest resource into the rarest kind of mana its color can produce, paying one life once each turn for a single colorless. The body is built to survive that toll. A 3/5 blocks all day and trades up against the early aggression that would otherwise punish any life-payment engine, so the creature funding your colorless costs is also the one keeping you alive long enough to spend them. Devoid keeps it inside the Eldrazi family even as it does a fixer's job, so a deck leaning on cards with colorless requirements in their costs or activations gets a creature that both wears down attackers and feeds them. The once-each-turn clamp is the restriction doing the balancing: this is a slow drip, not a ritual, which keeps it from accelerating into anything explosive and frames it as a body that happens to manufacture colorless rather than a mana engine that happens to have a body. It belongs to the lineage of utility creatures that pay life to smooth a mana base, with the wrinkle that the mana it buys is exactly the kind black has the hardest time finding anywhere else.