Kojiro Nanjo (南なん城じょう 虎次こじ郎ろう Nanjō Kojirō?), known in "S" as Joe (ジョー Jō?), is a character in the SK8 the Infinity anime series. A skilled skater and founding member of "S", he uses his unique build and stature to skate in an aggressive, movement-orientated fashion.

In "S", Joe seems to be a playboy who likes to charm and have fun with many women. This is shown at the beginning of Episode 1 when he kisses 2 girls simultaneously, and episodes later, he is seen flirting with countless girls.

Despite his aura of hostility towards Cherry Blossom, they are good friends who have the utmost trust in each other and their abilities. He is shown to deeply care for Kaoru, being the person Kaoru sneaks out of the hospital for after he's injured, and the one who carried Kaoru when he passed out after Adam's attack. Kojiro & Kaoru have been shown to be close, using each other's first names alongside the childhood friends aspect. Kojiro is extremely loyal to Kaoru and likewise for Kaoru.

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