Norn's Choirmaster

Proliferate has always been a payoff mechanic in search of a reliable engine, and this angel wires the engine directly into the command zone. The trigger keys off the one permanent every deck is guaranteed to cast and recast: your commander. Every time it enters (from the command zone, from a flicker, from a return-to-hand loop) or swings into combat, counters multiply across the board. That reframes proliferate from a one-shot spell you jam when you happen to have counters lying around into a recurring tax that fires on the game's most repeatable action. The design cares nothing about what kind of counters you are stacking, which is the point: +1/+1 counters on a go-wide board, loyalty on planeswalkers, charge counters on artifact engines, poison on an opponent you are racing to close, oil counters left over from Phyrexian designs. What ties the deckbuilding together is the attack clause: because a commander swinging is one of the two events that fire the trigger, the value line and the aggressive line stop competing. A commander built to be in combat is a commander that proliferates every turn, and the 5/4 flying, first strike body means the Choirmaster is happy to lead that charge itself. This is the counters-matter commander support that white had been circling: not another anthem effect, but a structural reason to build a deck where the numbers only ever climb, growing a little more with every commander cast and every commander swing.