User blog:Wirdang/why not caribou on the crew ????

reading all the blog posts and comments about this topic makes me think.why not caribou on the crew. what's the reason why caribous is still held captive by the strawhats? they don't need him as a guide going to fishman island because in the first place the strawhats was never asking for any direction to anybody. the only intention he is in the crew is he tried to kill the strawhats but was incapable and was held captive, so does that mean that when they reach fishman island, he'l be set free? then the element of introducing caribou in a very good, fancy and awesome way by oda will lead to nothing, there must be something worth about the character of caribou.