In the film, teacher Kitano cares for Noriko, wishing her to win the game and reveals a picture of her as the victor when she, Nanahara and Kawada break into the school.
In the novel and manga, Kiriyama is a sociopath with the mind of a genius and the inability to feel emotion, due to brain damage from a car crash in his childhood (in utero in the novel) that led to partial lobotomy.
Kiriyama has a great intuitive grasp of everything, enabling him to not only do outstanding schoolwork, but also to master normally time-consuming skills such as painting, playing the violin, and various martial arts at a rapid rate.
During his time in school, Kiriyama became the leader of his own gang, consisting of Mitsuru Numai, Sho Tsukioka, Hiroshi Kuronaga, and Ryuhei Sasagawa.
Gained weapons- Colt Python, 2 hand grenades, Uzi Kills: Hiroshi Kuronaga, Ryuhei Sasagawa, Izumi Kanai, Mitsuru Numai, Yumiko Kusaka, Yukiko Kitano, Sho Tsukioka (film), Yutaka Seto, Toshinori Oda, Mitsuko Soma, Shogo Kawada (post-game); Shinji Mimura, Mizuho Inada (novel and manga); Keita Iijima (film); Kayoko Kotohiki, Hiroki Sugimura (manga)± Killed by: Shogo Kawada (film); Shuya Nanahara (manga); Noriko Nakagawa (novel) Girl #11, Mitsuko Souma (相馬 光子, Sōma Mitsuko) is beautiful and seductive on the outside yet inside, she's a hollow shell, having been left permanently damaged after suffering physical and sexual abuse from her stepfather.
Similar to Kazuo Kiriyama, Mitsuko suffers from childhood trauma, and she is the leader of her own gang, which consists of Hirono Shimizu and Yoshimi Yahagi.
However, due to his sociopathic behavior, Kiriyama did not fall for her act and proceeded to injure Mitsuko by regularly shooting her in random parts of her body which left her in agony and caused her to remember various moments of her life.
Kiriyama then proceeded to end Mitsuko's life by shooting her through the face which destroyed her nose and eventually resulted in her death seconds later with her final thoughts being composed of her calling for her biological father and that he'd promised not to leave her.
In both the extended and standard versions of the film, she is depicted more to have been a socially awkward, anxiously vain outcast and loner with no friends who, upon provision of a lethal weapon and one very lucky encounter with a bitter classmate, broke down to desperation, madness and highly potentiated, wanton homicidality under the pressure of both the Program and her own mental disorders than the hyper-criminal, deeply feared school bully of the novel or manga (on the bus, a schoolgirl loudly and repeatedly, though not maliciously, disturbs her nap–Mitsuko says and does nothing; a scene depicting another female character being harassed by three female classmates at Shiroiwa High School does not see Souma as a perpetrator; additionally, she is herself terrorized at gunpoint by another female student, having "always pissed [the student] off".
In a series of flashbacks, it was also revealed that Shinji's uncle was a spy who taught him many things including how to hack systems and also how to make a bomb from items scattered around the island.
Another flashback shows him falling in love with Kayoko's "beauty & grace" when watching her from afar during her flower arrangement classes, his martial arts teacher made the remark "she'd be good for you" leaving Hiroki red and embarrassed.
In the manga, Keita is known to vomit in disgust when he sees something revolting, such as when Kazuo Kiriyama plucks out the eyeball of a gym teacher and crushes it in front of everyone, and when Yonemi Kamon shows the class the decaying corpse of Masao Hayashida.
In the novel and manga, little more than an ugly rich kid (his father owning a successful produce company) with high views of himself, Toshinori sets out to preserve his talents with the violin.
He is noted as the loudest and most arrogant member of the gang and was extremely grateful to Kazuo, after he pulled some strings to stop his younger brother from being arrested by the cops.
In the film, he and Tadakatsu are seen nude, stabbed to death while Mitsuko, putting on her clothes, leaves the area, implying that she seduced them to lower their guard and struck when they were most oblivious.
Being the polar opposite to his fellow gang member Mitsuru Numai, Sho has no loyalty and decides to betray Kazuo and not meet him at the reef, correctly predicting it to be a trap.
A breeze opens the bathroom stall door, showing that Kiriyama has rigged a water bottle over the toilet, creating the sound of urinating.
At this point Mitsuko attempts to kill him by slicing his jugular vein with a razor while they are kissing, however due to his amazing reflexes he developed while being in the baseball team, he narrowly avoids death, only receiving a small cut.
Driven insane by his desire to live and to please his father, Kyoichi attacks Shuya, but has his arm blown off by Shogo, who continues to blow a hole in his stomach, killing him.
She, like several other girls in her class, has a crush on Shuya Nanahara whom she met in elementary school in April on a rainy day while trying to organize the volleyball and little league teams in the gym.
After Hiroki Sugimura delivers an injured Shuya Nanahara to the lighthouse after an encounter with Kiriyama, Yukie takes care of him and dresses his wounds; she also convinces the other girls to let him stay.
Shortly after she kills Satomi, Yukie laments the lack of trust of her friends (In the Japanese version, her final word is "baka" meaning "moron", "fool" and/or "idiot").
Yuko realizes that Shuya is responsible for saving her life, even though he suffers agonizing pain, and this leads her to realise that he is good after all; her friends died in vain.
In the manga Toshinori pushes Hirono down the well, where she drowns during a final dream in which she climbs out, her dehydration gone, and finds Shuya and company who deactivate and remove her collar and tell her there is a way to escape the game.
After Shogo Kawada is declared the winner, Kitano orders the military to leave the island and to not bother to check for the bodies of Shuya Nanahara and Noriko.
In the novel and manga versions of Battle Royale Shogo carries a bird call Keiko had given him, and uses it as a signal should any of the main group get lost or, in the case of Sugimura, succeed in finding Kayoko let them know he found her.
He is executed when he pleads for the lives of the 3-B students and his corpse is left to decay for a while before being shown to his former class by their new "teacher" who tells them that this is the fate that befalls those who would defy the Program.
As each and every one of his friends gradually die during the game, Taku begins to show a much more brutal, cold side, and, eventually, he confronts the terrorist his entire class was sent to kill: Shuya Nanahara, who disarms them and attempts to persuade them to join his cause.
A kleptomaniac who tried to gain her mother's attention, and was in change transferred to Shikanotoride, Mifune hangs out with Kazumi and Ai as part of the delinquent girls, but doesn't feel a particular friendship towards them.
Abused as a child, Hibiki grew timid, weak and panicked easily (as she was shown screaming during the landing scene, with her classmates trying to calm her down); she was friends with Eri Yoshiyama, and both of them died when a random Wild Seven Sniper blows up their boat.