Gau, Feral Youth

The two abilities point in opposite directions, and that friction is the whole design. The Rage trigger wants a beatdown creature: attack, grow, attack bigger, snowball a 2/2 into a genuine threat over a few turns. The end-step clause wants something else entirely, a graveyard hobbyist who churns cards out of the yard for a burst of noncombat damage to each opponent. The clever part is that the counters feed both plans at once: every point of power Rage stacks on becomes the damage number the end-step ping reads off of, so the same growth that makes Gau a nastier attacker also scales the reach. That end-step clause is deliberately loose about how a card leaves your graveyard: a flashback cast, a delve, an escape, a Snapcaster-style recursion, a scavenge, or plain graveyard hate pointed at your own bin all satisfy it, which turns the ability into a reward for any deck already recurring or exiling from its own bin rather than a build-around that demands a dedicated engine. The result is a two-mana legend that reads as an aggressive body but pays out best in a shell that recycles its graveyard turn after turn, letting the combat step and the end step each cash in on the same accumulating power.