The thing is, in Japanese culture I have (anecdotally) observed that they do not see any form of imitation as appropriation, rather, they really appreciate it when people imitate their culture.

Not saying that this is exactly Japanese culture, but Rui also brands himself as the “Black Samurai” (Ninja moves by bron).

Plus given their friendship, my guess this is acceptable. Vs me doing it to some random asian person on the street, would not be.