The Last Agni Kai (TLA)

Instant

Target creature you control fights target creature an opponent controls. If the creature the opponent controls is dealt excess damage this way, add that much {R}. Until end of turn, you don't lose unspent red mana as steps and phases end.

Reliable combat trick and mana engine for aggressive red decks. The Last Agni Kai efficiently removes blockers while generating mana from overkill damage, turning combat into a resource generator. The mana retention clause lets you bank excess red into follow-up plays the same turn, rewarding aggressive sequencing in Standard, Pioneer, and Commander. Best in decks with oversized creatures or repeated combat phases, where the damage overflow becomes meaningful.

Avatar: The Last Airbender — Rare