MTL - Comprehensive Manga: a Journey Through the Supreme Being - Chapter 41

He was the merciless Soldier King on the battlefield who sent shivers down the enemies' spines; he was the soldier scoundrel in his squad who could make anyone both cry and laugh; he was the Big Brother everyone in the urban underworld aspired to be; he was the male god in the hearts of young girls and beautiful women; he returned with a mission...Uniting the underworld, establishing an economic empire, he vowed to become the supreme overlord of this world...To prevent the world from destruction, to protect world peace, to implement love and truth's evil, the lovely and charming antagonist, he is Xiang Yu, and he speaks for himself...

A tree of 10,000 flowers, the world is the door.
The spells change a lot, but the hearts of the people are unchanged.

- Description from Uukanshu translation

Alex, a special operative on Earth who died during a mission, finds himself transmigrated with the identity of an investigative journalist as an agent of a mysterious entity with a simple mission.With the promise that he would be reunited with his family once he was done, Alex accepts the offer and becomes an agent of darkness in a new world teeming with steam-powered machinery and something more... The supernatural.In this new world, he will have to navigate his way through crazy witches, bloodthirsty monsters, religious fanatics, and fallen angels while slowly making his way toward his end goal... Returning to the family he left behind.A journalist by day and a hunter by night, this is the story of the Hunter of Evernight.

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.