Fire Lord Azula

Spellcopy has always been an instant-speed reward: cast something worth doubling, then chain a copy trigger before the window closes. This design moves the reward into the combat step and hangs it on a body that has to be attacking to pay off. The Firebending 2 trigger fills your pool with two red the moment she swings, which is not incidental: it is the fuel the copy clause was built to consume, so a swing plus a spell resolves as a doubled turn on the same combat. Copying "that spell," not just an instant or sorcery, is the wide part. A creature spell resolves twice, a burn spell hits twice, a ritual doubles into more mana, and every copy lets you pick fresh targets. The constraint doing the balancing is exposure: she has to commit to the red zone as a 4/4 before any of it happens, so the payoff lives in a phase where she can be answered. But the timing is friendlier than it looks. You get priority in the Declare Attackers step, before blockers are even declared, so the Firebending mana is live and the copy trigger is armed the instant she is announced as an attacker. That places her in a specific lineage of Grixis spell-doublers that ask you to send a creature into combat first and cash the value after, trading the safety of a passive engine for the ceiling of a doubled turn.