The Successor's Game

"How should I decide who is perfect person for my successor?"

"I got it. I will drop them all in a multiverse game and then the winner can become my successor."

"But there are too many people, how should I look after them?"

"Oh yes, I can make fragments of a part of myself and let each fragment take care of a single contestants of the game."

"Hmm... That person should be strong, smart and kind. Let's give our contestants a task to gather companions."

"Oh yes, I will lottery to decide to decide which fragment which look after whom."

And thus Kouki and his sister Koyori got caught in middle of god's whim.