Isuzu Mikoshiba

Isuzu Mikoshiba is a minor character in the Free! series. She is Seijuro Mikoshiba's younger sister, and Momotaro Mikoshiba's older sister. She is the captain of Hidaka University High School's Swim Team, also known as the Taka U High School Swim Team.

Isuzu is of average height but well-toned. She has russet-colored hair and amber-colored eyes.

Isuzu is a vivacious young woman who enjoys swimming and playing video games. She is highly competitive and so confident about her abilities as an athlete that as soon as she is introduced to Haruka Nanase, she challenges him to a race, the idea of which her older brother immediately dismisses. She, like Gou Matsuoka, is obsessed with muscles and when the two first meet, they immediately bond over this fact.

(Source: Free! Fandom Wikia)