Mardu Hateblade

A white one-drop whose whole reason to exist is the black mana written into its activation. Left alone, the body is the bare minimum a creature can offer; the deathtouch grant is what gives it a job, and the off-color cost is the design's argument. This is a white creature that only reaches its ceiling once black mana is on the table, a small instance of the multicolor-incentive structure that rewarded players for committing to a second color rather than splashing one. Because the grant fires at instant speed, it punishes an opponent who declares an attack assuming a one-power blocker is a free trade: the deathtouch arrives in response to the block, after the math has already been done, and a single point of damage is suddenly enough to kill whatever swung in. The body itself almost never survives that exchange, so the deterrent is a one-time threat rather than a standing wall: it offers to trade up, dragging a larger creature down with it if the attack comes through. The repeatability lives in the activation, not the creature, which is the honest read on what one toughness can promise. Modest by any rate, but precise about what it asks for: not a second card, just a second color.