Kung Fu Panda 3 (2016) -

The Spirit Realm and the history of Kai and Oogway remind us that even the greatest masters have shadows. Oogway’s past isn't pristine; his friend Kai became a monster because of a thirst for power that they once shared. The film suggests that legacy isn't about being perfect—it's about the choices we make to move toward the light, even when our history is heavy.

Kai’s tragedy was that he wanted everyone's Chi but had no identity of his own (after 500 years, no one even remembered his name). Po’s victory was that he knew exactly who he was, and that made him untouchable. Kung Fu Panda 3 (2016)

Here is a deep take on why Po’s third journey remains an emotional high point for the franchise: 1. The Paradox of Mastery The Spirit Realm and the history of Kai