@Albino 👑
Just responding to your post to me.
I think he can fill the role of Ship Guard. Its a legitimate role in the series (Nyaban Bros had it), and it fits his DF power of reflection very nicely. He also guarded the crew ship for 2 years lol.
The way Oda focuses on Kuma's past is very unique to strawhats imo, save for maybe Law (who is probably Luffy's closest ally anyway)