Alright here is the short verse of my story. I'm originally from universe 10. I was a supreme Kai in training by the name of Zamasu. I saw mortals as nothing more than a mistake. Constantly repeating the same mistakes in an endless cycle. War, disease, litter, cutting down trees, forests, and destroying their own home. I used the Super Dragon Balls to switch bodies with Goku. I then killed my master Gowasu, Goku, his entire family, billions of mortals, cleansing planet after planet, oh and I'm also responsible for Future Trunks timeline being erased by Zeno. Future Trunks now lives in another alternate timeline of his but with another verse of himself and Mai. He has recently decided to live in the past with Goku and Vegeta. I was wished back with the Super Dragon Balls by Goku and we came to some sort of an agreement so we're sort of friends I guess. Goku and I have also been training together. We share each other's techniques. I've learned and mastered Ultra Instinct. So in returned I have taught Goku how to duplicate his form, the ki blade and scythe, among other things. I have tried to teach Goku Super Saiyan Rose but I guess thats just a unique form only I can use due to my original form being a Kai.