Bloodthirsty Aerialist

The trigger is deliberately loose: not "whenever you cast a lifegain spell" or "at end of turn if you gained life," but a counter for every single life-gain event, no matter how small. That distinction is the whole engine. It means a single Sorin's Thirst, a lifelinked attacker connecting twice, or a soul-warden effect ticking once per creature each feed the same growing body, and multi-instance sources stack their triggers rather than rounding down to one. A 2/3 flyer for three mana is a fair rate on its own; the ability turns lifegain, historically the least aggressive thing black and white do, into a clock. That is the inversion worth noting. Lifegain has always been positioned as a stabilizing, defensive resource, the thing you do when you are behind. Here it becomes the thing that closes the game, and the flying keyword ensures the accumulated counters land past most ground blockers. The counters are also permanent, so the growth persists through end-of-turn resets and survives anything short of removal; the card does not ask you to gain life on any particular turn, only to keep gaining it. It sits at the head of a small lineage of payoffs that reward the lifegain axis as an offensive strategy rather than a survival one, and its instruction is the cleanest expression of that idea: any life, any source, one counter.