A brief description of the manga The World’s Best Assassin, Reincarnated In A Different World As An Aristocrat:
The virtuoso killer got old and decided to retire. However, a man who can skillfully kill and do other “dark” things can not leave alone the powerful people. Wealthy people who are not doing the purest things, decide to “order” the same grandfather.
Eventually, the old killer dies, intending to go to the other world. That wasn’t it! The talent of the killer came in the spirit of a goddess who decides to give the dead a new body and set him the task – to kill …