Gunki Itoshima

Itoshima is eccentric, self-assured and comfortable occupying a leadership position among students who are themselves extremely difficult to manage. His behavior reflects the Plus Six's broader separation from ordinary social expectations.

He shares the group's dismissive attitude toward Normals and shows little interest in moderating himself simply to make cooperation easier.

His role as leader does not mean that the Plus Six behave like a conventional hierarchy. Their extreme individualism makes coordination difficult, and Itoshima's authority exists within a group specifically characterized by its troublesome personalities.

Itoshima's ability is associated with Command. The manga provides considerably less detailed demonstration of his individual power than it does for central Thirteen Party members, leaving the full mechanics and limits of his ability underexplored.

His placement as leader of the Plus Six nevertheless identifies him as one of the more formidable Abnormals associated with the Flask Plan. He occupies the second floor of the underground facility and belongs to the select group capable of freely navigating its deeper levels.

Like the other Plus Six members, his value to the Flask Plan derives from an extreme deviation from ordinary human ability rather than conventional academic achievement alone.

Itoshima appears as part of the Plus Six during the Flask Plan conflict. The group consists of Abnormals unknown to Maguro, establishing that significant changes have occurred within the project since Maguro abandoned his involvement.

The Plus Six expand the scale of the Thirteen Party beyond the opponents already encountered by the Student Council. Their personalities are so difficult that they are retrospectively associated with the same kind of social incompatibility that later defines Class -13.

Itoshima remains primarily a representative of this group rather than receiving an extended individual battle or personal arc.

Maguro Kurokami does not know Itoshima or the other Plus Six members, indicating that they entered the Flask Plan after Maguro Kurokami's departure.

Hamaya Hyakuchou is another prominent Plus Six member and one of the group's strongest figures.

Shoko Kamimine serves alongside Itoshima as a member of the Plus Six.

Youka Naze supervises important portions of the Flask Plan in which Itoshima and the Plus Six participate.

Oudo Miyakonojou is one of the central Thirteen Party members operating within the same Flask Plan structure.