Becoming a demon and traveling to another world

After traveling through time, he was adopted by a man named [God of Fighting].
He obviously has powerful magic power but is completely unable to control it.
But it doesn't matter!The boundary gate is activated!
Go to a new world and become stronger while finding the secrets of time travel.
The first world: Did you go wrong looking for encounters in the dungeon?
PS: The author is a newbie. The writing and plot in the previous paragraph are poor. I am slowly growing by absorbing opinions!