Knight of Dusk

Black creatures built around the threat of attacking are a strange place for the color to spend its energy, and this one weaponizes a window most cards ignore: the declare-blockers step of its own combat. The ability does nothing on someone else's turn, nothing against a creature attacking into you, nothing while the Knight sits back. It only fires after a blocker has already committed, and only against that one blocker, because each activation of kills exactly one. That narrow targeting and per-activation cost is the discipline holding the design together. Spend the mana once and you peel off a single defender, making it pay for the decision to step in front; the Knight survives against a lone small blocker without spending anything at all. The catch is the one the rules impose: a blocked attacker without trample deals no combat damage to the player even if its blocker is destroyed, so removing the blocker does not push damage through, it only clears the board. The 2/2 body never looked impressive on rate, and it invites a removal spell before the activation ever matters. What makes the structure worth noting is how it inverts black's usual path-clearing. Most of the color's evasion comes from fear or from killing the blocker preemptively at sorcery speed; here the blocker commits first, then pays for it, turning the act of blocking into a liability rather than a defense.