The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat, Vol. 4 LN

Word has gotten out about Lugh's ability to kill the unkillable demons, and now every major power in the world is trying to garner his favor. Yet, while many requests pass his ears, the first to grab his attention comes from Nevan, the talented daughter of a duke in the Alvanian Kingdom. As she tells it, the prince of the kingdom has fallen to corruption--and she wants Lugh to assassinate him! Looks like some crooked rulers are about to meet their maker!