Fujii Yakumo

A boy characterized by his slit eyes. On his way home from work, he meets the heroine, Sanjiyan (a three-eyed demon), named Pai, and becomes immortal to protect Sanjiyan, turning into "Wu". He embarks on a journey with Pai to become human. The age at which he became immortal is 16, a high school second-year student. As the story progresses, there are depictions of advancing times, but since he does not age after becoming immortal, there is no change in appearance.

He has a nature that dislikes fighting, and he tends not to take lives, even if they are enemies, often helping at his own risk. Especially against female-type monsters, his restraint is noticeable, and he often falls into a predicament being betrayed. He is good at cooking. "Give me a break" and "Yakui (meaning 'dangerous')" are his catchphrases. He seems to have a fear of heights, and he is not good at Chinese.

Originally, he was just an ordinary person who had gained immortality without any combat abilities. In the early stages, his only method of attack was reckless charges, relying entirely on his inability to die.

From the second part onward, he mastered martial arts and Beast Magic, allowing him to fight on equal terms with his enemies. However, as a sorcerer, he remained relatively weak, often struggling against top-tier demons such as Benares.

Through the training of the Five Generals of the Demon-Eyed King and the guidance of the Grand Sorcerer Madurai, he inherited new abilities and underwent countless battles, experiencing significant growth. Ultimately, he became the only being capable of standing against Benares and the Demon-Eyed King.