Magic Knights are modern magic-users who fight with weapons converted from their souls. Ikki Kurogane goes to a school for these Magic Knights, but he is the "Failed Knight" or "Worst One" who is failing because he has no magical skills. However, one day, he is challenged to a duel by Stella, a foreign princess and the "Number One" student. In this duel, "the loser must be obedient for life."

Kanan the “Gourmet Devil” has descended upon the human world with one goal: to gorge herself on youthful souls. Her first target is high schooler Youji Kyougi—except her plan backfires horribly! Instead of her meal, he’s now her…boyfriend?! Even though she’s lived for thousands of years, Kanan has never known love! Can a devil survive the dangers of dates, hand-holding, and her very first romance?

Amnesiac Caiman seeks to undo his lizard head curse by killing the sorcerer responsible, with his friend Nikaido's help. In the Hole, that's a threat.