Black Clover: The Underwater Temple

 The Underwater Temple is an area under the ocean, in a strong magic region, where the mana force fields are so strong, the currents prevent even upper-class mages from entering. As such, not many people visit the area, and the people there are very excited to see people from above water. The inhabitants have an alternate appearance as sea creatures. The temple is said to hold one of the magic stones, which are being collected by the Eye of the Midnight Sun, and the Wizard King send the Black Bulls to retrieve it.

Gifso

The temple's High Priest, Gifso is an older man who is fond of games. When the Black Bulls arrive, he forces the team (except Yami, due to his strength) to play a game with the deal that he will give them the stone if they win it. He even uses this game as a condition to let his grandchildren, Kahono and Kiato, visit the surface. He is the wielder of Game Magic, which allows him to create a dimension for playing grand games with rules. However, even when the game is in motion, he cannot enter the dimension or interrupt the game.

Gio

Son of the High Priest, Gio is the strongest magic user in the Underwater Temple. He uses Water Magic. While initially, he faces both Luck and Magna, their battle is interrupted by Vetto and is immediately defeated.

Kiato

Grandson of the High Priest and Kahono's older brother. Kiato is a Dance Magic-user, allowing him to use powerful sword attacks and make his movements hard to predict with his dances. He dreams of going above ground to become an idol, forming a Singing/Dancing duo with Kahono. He duels Asta, but they are interrupted by the attack of Vetto. He has his leg amputated by Vetto during their fight, but the Witch Queen's Blood Magic later restores it. He has a crush on Noelle after seeing her Water Magic, and calls her "Sea Goddess."

Kahono

Kahono is the lively granddaughter of the High Priest and Kiato's younger sister, possessing a sixth sense and using her Song Magic for various uses, including offence, healing, and putting the afflicted to sleep. She also has dreams of becoming an idol with her brother, confiding it to Asta and Noelle while helping the latter learn to use her magic effectively. Kahono later served as an opposition to the Black Bulls before helping them fend off Vetto which ended with her throat crushed by him, rendering her unable to use her magic's full potential. Her throat is later healed by the Witch Queen's Blood Magic when she was invited to the Star Awards Festival.