Rise of the Strongest War God - Chapter 54 Uninjured

Liola—the best assassin in his world—has vowed to kill no more. He was being chased by an assassination organization when he accidentally dropped into a parallel universe: through a dimensional gate and into poor teenager Kaiser’s apartment. Instead of going to the government shelter for lost dimensional travelers, Liola and Kaiser wind up going to school together.

Liola has been trying his best to live the life of an ordinary person, but after certain things happen one after the other, he begins to realize that being an ordinary person could be harder than being an assassin.

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

Lingyun, a fierce and savage cultivation genius takes over a dead teenager’s body. Coincidentally, they are both named Lingyun. Set in a alternate version of the 21st century, teenager Lingyun has been killed by someone with a grudge.

- Description from Novelupdates

This novel is about Chen Feng, a down on his luck kid of unknown origin, and the famed trash of a backwater sect. He is so unlucky, he even ended up getting struck by someone else’s Tribulation Lightning. And yet, maybe not.

For when the Tribulation Lightning descended upon him, it triggered something that he had been carrying with him all this time, granting him a cultivation technique so powerful, it would turn his world upside down.