Rampaging Soulrager

A defensive body that pays you for engaging with a mechanic most decks treat as incidental. The 1/4 frame is the tell: it survives early combat and holds a flank while you assemble the condition, and the reward for unlocking a second door is a swing to attacking size without touching the toughness. That asymmetry matters, because the buff is power-only. Whether the doors are open or shut, the creature keeps blocking through the same range of attackers, so the drawback of not meeting the condition is simply a stalled clock rather than a dead card. Because each Room's two halves unlock separately, "two or more unlocked doors" is less a build-around ask than a natural byproduct of running a few of them and progressing them over a game. The lineage here is the old red beater whose stats live behind a condition (the pump-when-you-cast beaters that trade a stable body for a conditional payoff), reworked so the condition is a board-state you build toward rather than a spell you cast in a window. What keeps it grounded is that the ceiling and the floor are both fixed and visible from turn one: no scaling, no snowball, just a wall that becomes a competent attacker once the doors are open.