Dion, Bahamut's Dominant // Bahamut, Warden of Light

The design tension lives in a six-mana, full-turn tax you choose to pay: the sorcery-speed exile-and-return is a commitment you make only when the board is stable enough to spend a turn investing rather than defending. The 3/3 front side is already a competent two-for-one, handing flying to your Knights and dropping a 2/2 alongside itself, and nothing about it demands you flip. What the transform buys is a Saga that reads like a payoff for exactly the token-heavy board the front side builds: two chapters of anthem-plus-evasion (a +1/+1 counter and flying on each other creature you control, twice), then a Gigaflare chapter that destroys any permanent before resetting Bahamut face up to start the loop again. The counters persist after the flying wears off, so each cycle ratchets your team's floor higher while the final chapter clears the single permanent stopping the swing. The structural cleverness is that the Saga never sacrifices itself: it re-enters front-side-up after chapter three, so the engine is a renewable removal-plus-anthem cadence rather than a one-shot ultimate. This is top-end that asks you to earn its ceiling twice, once at the transform cost and again across three turns of lore counters, and it rewards a board that was already ahead by turning that lead into something close to unlosable.