Kai (Kung Fu Panda)

"Kai has returned!"

- Kai

Kai, also known as The Collector, is the main antagonist of Kung Fu Panda 3. He was the brother-in-arms of Oogway five hundred years ago, and is a powerful Spirit Warrior.

He was voiced by J.K. Simmons.

Backstory
Five hundred years in the past, Kai and Oogway were close friends and brothers-in-arms, and the two led a great army. One day, Oogway was injured in an ambush, and Kai carried him for days in search for help. The two eventually entered a panda village, who used their knowledge of chi to heal Oogway. The village taught Kai and Oogway how to use chi; however, Kai became consumed by a desire for power, and used his new chi abilities to take, rather than give. Oogway, upon seeing the darkness in his former friend's heart, turned on him and banished him to the Spirit Realm, where he resided for five hundred years.

Kung Fu Panda 3
Five hundred years later, a vengeful and power hungry Kai had schemed to return to the mortal realm. Having stolen the chi of every master in the Spirit Realm, Kai challenged Oogway to battle, and managed to defeat him, but not before he reveals that he has set one warrior on the path to defeat him. Using Oogway's chi, Kai returned to the mortal realm, and shortly upon arrival, unleashed jade warriors upon all of China. Crane and Mantis were sent to investigate, along with several other kung fu masters, but they were quickly overpowered by Kai and had their chi stolen.

After having stolen the chi of all the masters of China, Kai launched an assault on the Jade Palace, battling Master Shifu and the Furious Five. Despite Shifu and the Five's attempts to keep Kai at bay, they were ultimately defeated, their chi stolen. Tigress was the only one to escape, and she journeyed to the panda village to warn Po.

Kai eventually arrived at the Panda Village, and sent his jade warriors to find Po. However, his warriors were attacked by the panda villagers, distracting Kai long enough for Po to ambush him and catch him in the Wuxi Finger Hold. Po attempted to use the hold to banish Kai back to the Spirit Realm, but it didn't work, as the hold only works on mortals, while Kai was a spirit. Kai immediately overpowered Po, but as he was about to steal the chi of the entire village, Po grabbed Kai and used the Wuxi Finger Hold on himself, transporting both of them to the Spirit Realm.

Enraged, Kai attacked Po once more, and nearly stole his chi. However, the panda villagers used their own chi to save Po, who then used his own chi to overpower Kai. Undeterred, Kai vowed that he would eventually take Po's chi, even if it took him another five hundred years. Po then surrendered his chi to Kai, who was initially overjoyed. However, Po overloaded him with chi, causing Kai to explode into a burst of energy. After his death, the chi of all the warriors Kai had defeated were returned, restoring them.