|Previous Affiliation||Thirteen Party, Plus Six|
|Previous Position||Leader of the Plus Six|
|Manga Debut||Volume 6, Chapter 44|
|Anime Debut||Episode 6|
|Japanese Voice||Takuya Satō|
Gunki Itoshima (糸島 軍規, Itoshima Gunki) is a senior of Class 13 and a former member of the Flask Plan's Plus Six. His project name is Death Watch (死番虫, Desu Wacchi).
Itoshima is a seemingly hotheaded boy who declares that he is not so cowardly to leave a friend in need. Like the rest of the Plus Six, he adds "Let's try and get along." after his introduction. Like the other members of the Plus Six, he is considered a basis for Class -13, having a personality that separated him even from other Abnormals.
Itoshima wears a white monk-like robe with black flame decorations, as well as a red sash and purple pants. The robe leaves his chest exposed. He has light brown hair and blue eyes.
Thirteen Party Arc
The group first appear before Youka Naze and Itami Koga after they kidnap Medaka Kurokami, offering to slow down the Student Council while Oudo Miyakonojou brainwashes her. Afterwards, the group rides the elevator to the first floor, where Itoshima demands to know why Myouri Unzen, Shigusa Takachiho, and Kei Munakata are helping the Student Council. They are engaged by the Loser Team so that the Student Council can head down to the lower floors. He is protected from Munakata's gunfire by Shoko Kamimine. While the other members of the Plus Six battle the Loser Team, he and Hamaya Hyakuchou stand to the side. Myouri Unzen notes that the pair are exceptional members of the Plus Six and cautions Nekomi Nabeshima against making the first move against them. While Medaka and company prepare to descend to the thirteenth floor, Itoshima and the others are still fighting the Loser Team. Itoshima and Hyakuchou are still sitting on the sidelines. Later, Itoshima, along with the rest of the Plus Six and the Loser Team, is defeated by Misogi Kumagawa.
Kumagawa Incident Arc
Following the battle, Itoshima is sent to the hospital along with the rest of Kumagawa's victims. Instead of external wounds, those who got pierced through with the giant screws took severe mental damage. On August twenty-second, Itoshima is among Medaka's former enemies who show up to cheer for her during the President's Battle. He cheers for Medaka with her victory.
Kurokami Medaka's Successor Arc
Bouquet Toss To The Future Arc
Superhuman Physiology: Itoshima's Abnormality has not yet been identified, but his abilities are noted to be exceptional even by the standards of the Plus Six, and he is one of the two main candidates to be the group's leader, the other being Hyakuchou. He is one of the only members of the Flask Plan who can use the elevator in Hakoniwa Academy's underground facility, along with Unzen and the other members of the Plus Six.
- When translated from kanji, Death Watch means Death Guardian Worm, and is also synonymous with "Death Watch Beetle".