Haraeyu: Male. A Light Esper who can be considered Legendary-rank. He was initially ranked F-rank due to a Yokai residing within his body, but thanks to Elec, he defeated the Yokai and rose to S-rank.

Elec: Male. A Lightning Esper of Legendary-rank. Like Haraeyu, he became Legendary-rank after defeating the Yokai within his own body.

Yokai King: Male. Wields evil supernatural powers. He is the primordial Yokai and is Calamity-rank. Though he was born a Yokai, he was originally kind-hearted; however, he was abandoned by humans because of his dark powers, eventually leading him to turn humans into Yokai and become the King of Evil Yokai.

Yang-achi: Male. A Yokai who uses Fire powers. He can be considered Calamity-rank. He was originally an A-rank Fire Esper, but he turned himself into a Yokai in order to defeat the Yokai King who killed his parents.

Fire Esper: Female. A Fire Esper who also serves as the official Hero Rank Measurer.

Calamity Yokai: Male. A Yokai who uses Destruction powers.

Typhoon Yokai: Male. Uses Typhoon powers and is S-rank. He was originally a friend of the Fire Esper, but was turned into a Yokai by the Calamity Yokai.

Speeder: Female. A Yokai with evil Baseball powers. She is S-rank.

Nerd: Male. A Water Esper of C-rank.