What's worse, it's heavily implied that the reason nobody remembers Kai is because Oogway did something to force people to forget.Happily, under the fluid direction of Jennifer Yuh Nelson (who helmed “Kung Fu Panda 2”) and Alessandro Carloni, the new film never seems in danger of falling under that description, pulling us in with an otherworldly prologue set in the eternal Spirit Realm.
Over the course of the entire movie he's always upset that people don't remember him, to the point that when Po actually knows Kai's old nicknames and titles, Kai is so happy he almost wants to spare Po's life.
Even though he ended up becoming a bad guy, he still did a lot of good with Oogway before learning about Chi, even saying that he was once known all across China.
When he explains this to Shifu, he looks and sounds like he's on the verge of tears, a complete contrast to every other moment he's on screen. He truly doesn't understand why what he did was wrong, and thinks that his brother just turned on him for no reason. When Oogway "betrays" him, you can see a very hurt look on his face for a split-second before he fights back. The guy carried him for three days straight through a raging blizzard when he got injured in order to find a healer, and his expression there is both sad and fearful. To Kai's credit, it's clear that at one time, he genuinely cared for Oogway just as much.Imagine how Oogway had to feel when he sealed Kai away. Master Oogway's brother-in-arms who he cared for like family.turned into a power hungry psychopath who would steal people's souls for power.
You see the moment where Po realizes he can't get free and slowly closes his eyes as he loses consciousness. Po nearly being turned into a jombie by Kai while they're in the spirit realm.Mr Ping: He saved us.but who's saving him?