アニメ fans, I need help!!

Ok, there's this アニメ TV 表示する I watched a long time ago, and now I can't remember the name of it. For あなた アニメ fans, can あなた help me find out what's it called?

1.it was about a guy who went into his room one 日 and found a kid-like person in there. There was also a book(I think it was red). When the guy read the first line of the book, lightning struck his house, and he found out he made the kid preform a spell

2. the kid is from another dimension-thing where every number of years, they have to go to earth, battle, and the last person standing becomes king. または something like that.

You'll get リスペクト of あなた can tell me what this is!!Please help me!!