Returned from the Abyss

In an unknown abyss, where all the strongest species existed even Gods and Demons can't conquer, a human successfully entered but he died immediately because he can't stand the strong pressure of mana even though he's fully prepared. When his body died, his body started absorbing the mana in his surrounding. After a 988,000 years the body started to have a new conciousness.

He don't know who he is, but his head started to ache and the memories of the owner of the body entered to his brain. He learned that his name is Zero the strongest mage and the strongest swordsman in his world. He also learned that the owner of this body tried to enter the unknown land and immediately died. Now his body is stronger by 1 billion times because of the mana he absorbed can he clear this hell?

After ????? years he finally cleared that hell so what will Zero do now?

(I'm just doing this for fun and this is my first time creating novel.) LOL
Feel free to criticize my work :)