Arcbound Condor
Modular has always been a colorless mechanic: Arcbound creatures shuffle +1/+1 counters between artifact bodies without caring what color deck they sit in. Grafting that engine onto a black creature that punishes every artifact you play is the twist that reframes the whole line, because now the deck's artifact density does double duty. Each artifact you deploy shrinks something on the other side of the table by 1/1 until end of turn, which is enough to clear a blocker before a swing, finish off a creature already dinged in combat, or grind down a token board one drop at a time. Note what modular does and does not carry: when this dies, only its counters move to another artifact creature, not the shrink-trigger, so the redistribution is about preserving stats, not exporting the removal engine. The flying matters because a modular carrier wants its counters on something the opponent cannot easily block, and an evasive body that also polices the ground is doing two of black's favorite jobs at once. The design reads as a deliberate bridge between the mono-artifact Affinity lineage, where modular grew creatures without ever leaving colorless space, and black's long tradition of grindy removal stapled to a body. What it asks in return is exactly that density: the -1/-1 fires only when another artifact enters, so the card is inert in a shell that is not built around a steady drip of cheap artifacts. Less a standalone threat than the reason an artifact deck reaches for black at all.
