I quit the Straw Hats at the beginning and joined the Beast Group chapter 243

Time travel to pirates. At the beginning, at the invitation of the pirate king Luffy, Ren joined the Hat Pirates. But because he learned his lesson along the way and kept hitting enemies with low health, he had a dispute with other members of the Over-the-Blessed Mother's Hat Team. In anger, he quit the *Hat Pirates directly. As a half-blood of the Lunarian tribe, he unintentionally acquired the ability to take the form of the Cow Fruit, Phantom Beast Species, and Kirin Form. So Ren turned around and joined the Beast Pirates, and became Kaido's son-in-law and Yamato's fiancé. Before the war, he coldly refused Luffy's request for help. "Sorry, I don't want to play house with you anymore!" "From now on, please call me the fourth natural disaster of the Beast Pirates - Blood Prison Renn!" "Father-in-law, you have been on the throne of the most powerful creature in the sea, land and air for too long. It's time to step down and give way to others!" "I announce that from today onwards...the new Beasts Pirates will consist of all Phantom Beasts!" …