Kai Smith is the "Red Ninja of Fire" he used to work at a blacksmith shop, until he joined Sensei Wu to train in the art of Spinjitzu to save his sister from the skeletons serving Lord Garmadon. He wields the "Sword of Fire" and has a dragon named Flame, he was the last one to unlock his true potential but was the first one to discover the identity of the Green Ninja.