Once upon a time, There was one dimension. That dimension was ruled by two Gods. The God of Creation, Faya, and the God of Destuction, Yuu. They lived happely with each other, but then a great evil came to the world. It formed his way into Yuu's heart. Yuu felt something has changed within him, but to protect Faya and the humans, he didn't tell her. And then, one day, the evil in his heart had enough of not being able to do anything. Slowly Yuu felt the control over his body slipping away. He screamed in pain, but no-one heard him. The evil took control. Before that happend, Yuu spoke with the evil. No-one heard what they where saying, but one word was clear to understand.
Berserk..
After the evil, now known as Berserk, took control of Yuu's body, the world began to change. Monsters came and destroyed the land. Faya, who didn't know that Yuu/The Berserk made those monsters, used her power to create cards and energy blades. The humans could capture these monsters in the cards and summon them on the energy blade to have them help them in this war. When Yuu/The Berserk saw this, he was furious. Yuu walked towards Faya and he killed her. Well, he thóught that he had killed her. What he didn't know, was that he had split her soul in four pieces. Faya's souls knew that they had to stop this war. They erased the memories of the humans about this war and rebuild the world. Then they floated to Yuu. They said something to him, and then split his soul into four pieces. But with the souls of the Gods now incomplete, the world split into four too.
Faya decided to name the worlds to the monsters types: Synchro, Xyz, Fusion and.. Standard.
Then, Yuu and Faya's souls disappeard. No-one would ever remember them.
Exept for… Genesis Omega Dragon..
And do you want to know what Faya said to Yuu?
"Yuu, i'm sorry. I still love you. I will guard you and save you from this evil. Yuu, until we meet again"