Lighthouse Chronologist

Extra turns are the most dangerous payoff in the game, so they almost always come stapled to a one-shot spell or a prohibitive cost. This one inverts the structure: it hands you the extra turn as a repeating engine, but gates it behind a level-up climb that costs blue mana, advances only at sorcery speed, and asks you to keep a fragile 1/3 alive across multiple turns before the reward ever triggers. The trigger does more design work than it looks. It fires on each end step that isn't yours, taking an extra turn after the current one, which means the loop is built on symmetry-breaking: if every player is passing normally, the Chronologist quietly grants you a turn after each opponent's end step, so the more opponents there are, the faster the loop compounds. In a duel it's one extra turn per rotation, scaling upward as the table grows. The ceiling is paid for in exposure. The card sits inert on resolution, climbs at the pace of a sorcery, and reaching the top tier leaves you having sunk nine mana total (two to cast, seven to level up) into a 3/5 that any removal spell answers before the engine pays out. Everything about the design lives in the gap between investment and reward: a slow, telegraphed ascent toward an effect that, once online, is among the hardest things in the game to interact with.