I just realized that I don't know of any martial arts films (including stuff like Star Wars because it follows the same style of tropes) that ever have the Master becoming an arrogant kung fu guy.
It's always young ambitious whippersnappers who become arrogant in their prowess, and the wise-with-age older dudes who know how to be humble while still being able to inspire humility in said young ambitious whippersnappers.
But has there ever been a Master-Student relationship where it was the Master who lost his way, and not the student? And I don't mean cases where the Master has always been evil, but rather, turned to the "dark side" in old age, and admonishes the student for not immediately following him.