Shidou Itsuka

Age: 16

Height: 170 cm (5'7")

Weight: 58 kg

Blood type: A

Species: human

Affiliations: Raizen High School, Ratatoskr

Favorite quote: "If people refuse to accept you, I'll just accept you even more."

The main protagonist of the story, Shidou is a student of Raizen High School. He was adopted into the Itsuka family when he was "abandoned" by his mother. He possesses a strange power that allows him to seal the powers of a Spirit in his body with a kiss; however, the seal will only work if the Spirit holds enough trust or affection toward him to allow it. Although considering trust and affection is a two-way street he probably needs to have a certain amount of affection too, or at least genuinely want to help the spirit from the bottom of his heart which he usually does even before seeking out a spirit.

Due to this power which was already known by Kotori Itsuka he was recruited—or rather forced—to join "Ratatoskr" to help and save Spirits. Instead of killing Spirits to prevent spacequake from happening, he has to seal the Spirit's powers with a kiss in order for them to co-exist with humans.

An average teenage boy that originally had no interests in the opposite gender until he got forced to be by his little sister. Basically, he has to deal with females on a constant basis, which he is not used to. Shido is also a very kind-hearted person, and can sympathize with others; these traits are what caused most of the Spirits to fall in love with him, as the thing they seem to lack most of all has always been a person who can do exactly this: i.e. accept and understand them. Even Miku, who treated everyone like puppets, ended up changing her world view because of him.

Shido has the mysterious, and unique ability to seal the powers of the Spirits into his own body, which was first discovered sometime in the past when Kotori was turned into a Spirit. To use his ability to seal a Spirit’s power, the Spirit in question must meet a certain condition or requirement. Those conditions or requirements are that, the Spirit in question must show affection, trust, closeness, and/or intimacy towards Shidou. Once these conditions of affection are high enough between Shidou and the Spirit in question, he can seal their power by kissing them on the lips.

Depending on the Spirit itself and how much power they originally had, Shidou can either seal a majority of their power or all of it. Shidou can also “borrow” the power of a Spirit he sealed, but it depends on how close or intimate he is with that Spirit. This explains the nature of his regenerative abilities. However, it seems that using a Spirit's power (other than regeneration) taxes his body with great pain.