Seven years back, the parents of Yuto Amakawa perished in an auto crash, leaving him alone without the sole thing left of his household, a single relative being a mysterious and peculiar amulet given to him by his late grandma. Ever since that time, his childhood buddy Rinko Kuzaki (and her parents[ch. 1]) has cooked for and taken care of him. When he meets a cat demon samurai woman, Himari his life takes a radical turn. Himari discloses to him that a number of his ancestors were part of the twelve Demon Slayer families which were slaying demons because the feudal age. She's sworn an oath to protect Yuto from the devils which are out to destroy him, but the allergic reaction to cats of Yuto makes it fairly hard to take care of.
Later on, Yuto falls upon various women who take a liking to him: Shizuku, a mizuchi by means of of a little kid; Lizlet, a tsukumogami by means of of a busty tea-serving maid; and Kuesu, still another Demon Slayer who's revealed to be Yuto's fiancee as well as a man from Yuto's lost past.
As the show progresses, the group as well as Yuto fall upon some strong ayakashi, with a few of them being allies, and Yuto ultimately makes a life-altering choice to fight because of his opinion of co-existence between ayakashi and individual.
