In Kung Fu Panda 3, Kai is the spirit warrior who steals chi from kung fu masters.
Kai is a powerful yak-like supernatural figure and the main antagonist of the third film. After returning from the spirit realm, he attacks masters and captures their chi, converting them into jade-like jade zombies known as jombies. His goal is to absorb the chi of every kung fu master, including Po.
Kai’s history is linked to Master Oogway. The two were once allies, but Kai’s desire to control chi eventually turned him against Oogway. Their conflict explains why Kai spends time in the spirit realm before returning to the mortal world.
J. K. Simmons voices Kai in English. He is distinct from Tai Lung, the snow leopard villain of the first film, and Lord Shen, the peacock villain of the second. Kai’s supernatural powers and spirit-realm setting make him different from the more physically grounded earlier antagonists.