Shanna, Purifying Blade

The engine hides behind a resource most decks treat as spare change. Lifegain is usually a means to an end, a buffer that keeps you alive long enough to do the real work; here it becomes the metering device on a repeatable card-draw pump. The end-step trigger caps X at exactly the life you gained that turn, so the card asks a specific question every turn cycle: how much life did you actually bank, and how much mana can you spare to convert it? A single lifelink attack from a 3/3 already primes a draw or two, but the design opens all the way up the moment lifegain becomes something you do on purpose rather than something that happens to you. That is the tension that keeps it in check: the ceiling is self-imposed, drawn fresh each turn from a total you have to build before the end step arrives. Stack incidental gain, extra combat life, drain effects, and the payout scales with how deliberately you've assembled the turn rather than with raw mana. The three-color identity is doing real work too, pulling the lifegain-matters theme white and green have circled for years into a blue-shifted draw shell, which is a combination those colors rarely get to run through the same permanent.