Karin Koizumi

Karin is shy, gentle and polite, sharing much of Sena Kobayakawa's timid manner away from competition. She dislikes unnecessary confrontation and can appear out of place among Teikoku's intensely ambitious athletes.

Her personality changes noticeably once a play begins. Karin accepts the responsibility of quarterbacking Teikoku's first string and can perform decisively despite her quiet everyday demeanor.

She does not share the obsessive drive that brought many Teikoku players to the school, which makes her position particularly unusual: extraordinary ability comes naturally to someone who did not originally want football fame.

Karin's greatest skill is passing accuracy. Her throwing form produces a smooth, highly catchable spiral that allows Teikoku's receivers to maintain momentum rather than adjusting dramatically to the ball.

She lacks quarterback power compared with players such as Hiruma or Kid, bench pressing only 35 kg, but compensates through technique and placement. Her 4.9-second 40-yard dash also gives her respectable mobility.

Her talent is sufficiently exceptional for Teikoku to use her as its first-string quarterback despite the extraordinary competition for places on the Alexanders' roster.

Karin is discovered after an errant football comes toward her near Teikoku's field. Her instinctive return throw attracts Taka's attention, and the Alexanders recruit her after recognizing the quality of her passing.

Her existence is initially concealed from Deimon's understanding of Teikoku. When the teams finally prepare to meet, her role as first-string quarterback adds another unexpected elite player to an already overwhelming roster.

Karin quarterbacks Teikoku against Deimon in the Christmas Bowl. Although uncomfortable with the aggression surrounding the game, she continues directing the Alexanders' offense against the team attempting to end Teikoku's championship dynasty.

Taka Honjou discovers Karin's unusual passing ability and plays a central role in bringing her into Teikoku's football program.

Takeru Yamato frequently protects Karin away from the field and plays alongside her as one of Teikoku's offensive stars.

Sena Kobayakawa recognizes Karin's shy temperament immediately because it resembles his own.

Youichi Hiruma initially attempts to ensure Deimon does not hold back against Karin because she is a girl, treating her instead as the first-string quarterback of their opponent.