Why Can't a Reincarnated Demon God Be a Siscon?!

Yang Zihao was a struggling writer. One day, after meeting a little girl who claimed to be his older sister, he transmigrated.

The reincarnation of the strongest demon god? What does that have to do with me? I'm just a struggling writer. I came to this world only to gather material for my next book. Conquering the gods or anything like that never even crossed my mind!

...Hey, hey! Talk it out, don't touch my sister! You wanna be my brother-in-law or what, kora!!!