- Voiced by: Daisuke Ono (Drama CD), Takashi Kondo (anime), Kaori Akashi (anime, child) (Japanese), Chris Patton (English).
The protagonist of the series, Akuto transfers to Constant Magick Academy, hoping to someday become a high priest for the benefit of society. However, upon arriving, Yatagarasu, the school's oracular spirit, announces that he will become the Demon King in the future. As a result, the entire student body becomes terrified and paranoid of him. Even so, he tries to do the right thing when the situation arises. Akuto has an incredible amount of power within him that sometimes gets out of control. Akuto has a highly serious personality but not without some humor. In the manga, he has much more of a temper, and, in a fight, is unwilling to hold anything back. In the anime, he tries to restrain himself in order to convince everyone that he has no desire to be the Demon King.
Akuto is capable of controlling and manipulating "mana", a magical energy that resides in the bodies of living things and in surroundings. For instance, he is able to absorb the mana of a large demon dog, thus transforming it back into a normal puppy, a feat that has never been performed before. However, his immense power is also highly volatile and most of his early attempts at controlling mana and creating magical projectiles, no matter how benign they are supposed to be, resulted in catastrophic explosions.
- Theron Martin of Anime News Network describes Akuto's role in the series as "a case where the harem master is still basically a nice guy but also turns out to be his story's buffest and biggest bad-ass" and that "everything that Akuto says or does to prove that he is not a Demon King is instead misinterpreted in a way that only bolsters his image as a Demon King, including the way that he collects his harem, is a vastly amusing one which gets a lot of play throughout the series".
- His name is phonetically very similar to a Japanese phrase meaning "Great/Ultimate villain".