Shepherd of Heroes

A durable 3/4 flier whose lifegain scales from a token gesture on an empty board to a genuine race-reset with a full spread of the four party roles. Because it is itself a Cleric, its own arrival adds one member to the count the trigger reads, so the floor is never zero: two life minimum, eight at capacity. The design lives in that variance. Party caps you at one each of the four class types rather than rewarding depth in a single tribe, so the payoff measures breadth of deckbuilding rather than density, and a lifegain wall that counts to four is exactly the kind of reward that structure produces. The flying body holds the ground on defense whether or not the enters trigger lands big, which keeps the card useful even when you draw it before you have filled out your board; the burst is the bonus for having done the assembly work upstream. That Cleric line also tightens the loop between enabler and payoff: the creature contributing to the trigger and the creature scoring off it are the same permanent, which shortens the runway a party deck needs before this pays.