Manga Saihate No Paladin

William is the only man in the city of the dead. Born with vague memories of a past life in modern Japan, where he could not do anything useful, he is determined not to repeat the same mistake again and that this time his life will be lived. But what does that really mean? Raised by a group of undead, William must find out what circumstances brought him to this city and these people, as well as what it means not just to exist, but to live a full life.