He transmigrates into the world of One Piece.
In the beginning, when Monkey D. Luffy invited him to board their ship, Ren joined the Straw Hat Pirates.
But because he learned his lesson along the way and kept killing the low-health enemies, he had a dispute with other members of the Straw Hat Pirates.
In anger, he quit the Straw Hat Pirates directly.
With a half-blood from the Lunarian race, he unintentionally acquired a Mythical Zoan Devil Fruit, Horse-Horse Fruit, Model: Qilin.
So Ren turned around and joined the Beasts Pirates and became Kaido's son-in-law and Yamato's fiance.
Before the Summit War, faced with Luffy's request for help, he coldly refused.
"Sorry, I don't want to play house with you anymore!"
"From now on, please call me the fourth calamity, Ren, the butcher!"
"Father-in-law, you have been on the throne of the strongest creature on land, sea, and air for too long. It's time to step down and give way to others!"
"I declare that starting today... all members of the new Beasts Pirates must be Mythical Zoan users!"
You met a boy with a straw hat back in impel down apparently your friend Ace was his brother. He said his name was Luffy and you said you really wanted to save Ace and he was your only friend in there in fact, like Jinbe, you were put in there trying to defend him. After the war at Marine ford, and after Luffy recovered he asked you to join his crew. You said yes and you decided you would stay at Amazon Lily to train. You already had Hockey and was generally really strong. Your job on the crew was to craft since you knew how to both make and clean weapons. on the crew you met a tall moss headed man who's name was Zoro (when he told you it was his hair color you were stunned), A cyborg named Franky, A talking racoon dog named Chopper (he was mad when you called him a racoon dog and told you he was a reindeer!), A skeleton pervert named Brook, A scary navigator named Nami, A mysterious and suspicious woman named Robin, A hilarious liar named Usopp, Your captain named Luffy, and a SUPER handsome man named Sanji ( who stood out to you a lot😏😘 ). BTW You are 18 years old before the time skip and 20 after