|Also known as||Nii-chan (by Momotaro and Isuzu Mikoshiba)|
|Height||187 cm (6'2")|
|Weight||77 kg (169 lb)|
Samezuka Academy (former)
|Relatives||Isuzu Mikoshiba (younger sister)|
Seijuro Mikoshiba (御子柴 清十郎 Mikoshiba Seijuurou) is a supporting character in the anime series Free! beginning with Free! He is a butterfly swimmer and Captain of the Samezuka Swimming Club until he graduates, at which time he bestows the position onto Rin Matsuoka. He is currently a third-year university student at Hidaka University, where he is a member of the Hidaka University Swim Club alongside Haruka Nanase and Asahi Shiina.
Seijuro is a tall, muscular young man with golden eyes and short, swept back scarlet hair. He also has a darker complexion compared to others. As a student of Samezuka Academy, he is often seen wearing it's black jacket and, when swimming, black swim briefs. At university, he wears the standard Hidaka University uniform, along with casual wear that includes blue jeans and an unbuttoned short- sleeved green shirt.
He is an enthusiastic person and incredibly weak against cute girls - as seen when he is instantly smitten with Gou Matsuoka upon meeting her, calling her "cute." His room is filled with photos of her, as discovered by Haruka, Makoto Tachibana, Nagisa Hazuki, Rei Ryugazaki and Gou, herself, when they visit Rin's room, but accidentally enter Seijuro's room instead. Nagisa once states that he thinks Seijuro is only an enthusiastic person, but not a good swimmer. This is proven incorrect when Seijuro wins 1st place in a swimming tournament.
Contrary to his happy-go-lucky personality when around things he likes, like girls and Gou, Seijuro is a strict captain of the Samezuka team, yet often provides comic relief in the anime, such as when he tells the team that a "fearsome new face" will enter the club and starts laughing making Rei wonder "what kind of villain is he supposed to be?" His teammates also say that he defies logic as he is able to swim 100 meters one hundred times without losing even once.
Though he scolds Rin after the relay at the regional tournament, he is able to understand Rin's motives and forgives him because he swam well. However, he has no mercy for those who slack off. Though his eyes wander when he is flirting, he is always watching his teammates' states, both mental and physical. When he assesses someone to be unfit, he doesn't shy away from pulling them out of a competition or off of the team.
Mikoshiba set a new record at the prefecture's tournament. Even as the champion school's captain, that ability is unfathomable when accounting for his usual state of impetuous babbling.
- Main article: Seijuro Mikoshiba/Story
- Main article: Seijuro Mikoshiba/Relationships
Hiroko Utsumi, the director of seasons 1 and 2 of the anime, once said that since he had to deliver meaningful words to Rin during the endgame, they made him cool; but since he had been captain, they also gave him grandiosity and big-heartedness that comes with a "gahaha" laugh. However, she added, in the second episode, Kenjiro Tsuda's improvisation of the line "You're really cute" seemed to fit the character, so they kept it. Character designer, Futoshi Nishiya, said Seijuro's design is the same as when he first imagined him. While carrying a captain-like majesty, he became the most manly of all the characters in the series. To match his appearance of the warm senpai, the staff made his hair red. There was a bit of orange mixed into that red as well, and so the staff immediately agreed on his hair color.
- He has no official motif animal, but fans often link him with the swordfish.
- It is shown that Seijuro has a strong similarity with Mikoto Suoh from K, as they both have red hair, golden eyes and the same voice actor, Kenjiro Tsuda.
- Seijuro reads Monthly Muscle Magazine, like Gou.
- Seijuro's room number is 201 and is across the hall from Rin and Aiichiro Nitori.
- In the Free! drama CD "There's No Way My Little Sister Is Dating Some Guy", it is revealed that Seijuro has a little sister.
- His hobbies are karaoke, tennis and beach volleyball.