|Occupation||Middle school teacher|
|Japanese VA||Yasumichi Kushida|
|English VA||Parke Fech|
"I'm a teacher! No matter the situation, we will do what's right and just!" — Isamu Kondō
Isamu has a large, muscular built. His face sports a freshly shaved beard and several wrinkles around both his forehead and eyes. He bears short, spiky, dark brown hair. Isamu's attire consists of a dark green plain shirt, grey pants held up by a black belt, and dark sneakers. Like any other player in the Btooom! game, Isamu has an IC chip implanted in his left hand and carries a BIM pouch, which he carries on his waist.
Isamu is first seen promoting a pacifistic approach. However, he is later shown to have mentally prepared himself to resort to violence, especially when Masashi baits him into reaching for BIM pouch by pulling out his own BIM; Masashi suggests this to be proof of Isamu's hyposcrisy.
Isamu is also very opinionated. He is prideful of both his knowledge and his occupation as a teacher, occasionally exhibiting such behavior whenever lecturing his audience. Whenever his views are questioned, he becomes very sensitive, prompting him to justify that he either meets a qualification or that his reasons are moral.
Isamu mentions little of himself other than his occupation as a teacher and his claim of having a sixth-dan in judo.
On the morning of the first day, Isamu, along with Masashi Miyamoto and Mitsuo Akechi, discover Himiko asleep. Having suddenly approached her, the three unintentionally awaken Himiko, prompting her to scream. Startled, Isamu quickly comforts Himiko with words of peace and quickly explains the benefits of several people working together to survive. Afterward, he invites her to join their group. 
Later, Masashi reveals that rescue is improbable and adds they may have to kill in order to survive. However, Isamu objects, exclaiming that they should focus on their group instead. Irritated, Masashi insults Isamu. The argument then escalates drastically when Masashi reveals a cracker BIM, prompting Isamu to reach for his own BIM. After Masashi notes that Isamu mentally prepared himself for violence, he takes Himiko hostage. Masashi then taunts Isamu, stating that killing both himself and Himiko would prove Isamu as a hypocrite. Unexpectedly, Himiko produces a taser from her pocket and attempts to stun Masashi. Masashi quickly lets go. Shortly after, Mitsuo argues that they remove their weaponry in order to avoid conflicts. He then proposes the idea of electing a leader to watch over their weapons. The group then agree to have Himiko act as leader. 
At noon, Isamu discovers the other three members in possession of a supply package and comments of how unsightly the three of them look as they devour their newly-found rations. He begins to lecture the three on the importance of rationing. His lecture, however, is abruptly cut short when Masashi slits his throat with a combat knife. Isamu later succumbs to his wound. Soon after, his IC chip is possessed by Masashi. 
Equipment and skills
- Never observed using them, though he does reach for them at one point.
- Observed amount used: 0.
- Isamu gave Himiko his BIMs in order to watch over them on the first day. After his death, his ownership is passed onto Himiko.
Due to his large, muscular built, Isamu is capable of handling more strenuous tasks than others; this can be supported by Isamu's claim of having a sixth-dan in judo.
Isamu has been shown to be capable of thinking ahead in the future; he managed to not only form a group of four early on but saw the importance in rationing when others neglected to.
- His name is likely taken from Kondo Isami, a swordsman and the leader of the Shinsengumi during the Edo period.