Does Ace Join The Straw Hat Pirates. Hailing from the East Blue Luffy has slowly acquired a powerful crew with reliable people all of which are willing to give up their lives for him. Why Trafalgar Law is going to join the Straw Hat Pirates.
Yamato feel more part of the family when he does join Luffy and embarks on his grand adventure. In episode 897 Tama was wearing the straw hat. The only chance Ceasar has of joining is if he does something amazing and heroic like put his life in grave danger to rescue a Straw Hat or something that shows he has a good heart or is worthy of Luffys respect.
The Straw Hat Pirates are led by Monkey D.
If a Straw Hat crew member leaves the crew without Luffys permission Luffy does his best to recruit them back. Luffy the protagonist of One Piece and are the most important crew in the story. Before Nami and Robin also wore the Straw Hat and they both joined. This is done through Luffy defeating Doflamingo and further on fighting stronger and stronger opponents through Cracker Katakuri and now Kaido.