Kill no more manga

Kill No More summary:

An assassin who swore never to kill again - Liola, was being chased by an assassination organization when he accidentally dropped into a parallel universe. In this chaotic, unorganized world, Liola continues to honor his promise. He tries his best to live the life of an ordinary person, but after a series of events occured... He suddenly realized that actually, being an ordinary person is harder than being an assassin!