if mysterious, young man who has a hard time adjusting with his classmates because of his excellence in almost every subject (including academics and athletics). He hosts a popular late-night radio program which Natsumi compulsively listens to. Mutsumi is the least active main character of the series, but plays a significant role as Kururu's partner/friend, Natsumi's unrequited crush, Giroro's romantic rival, and probably the most intelligent human character. Through a chance encounter with Kururu at school, Mutsumi not only met and rescued him from a battle gone awry but also acquired his trademark weapon: a virtual reality pen created by Kururu that can create anything on any solid surface, exclusively for himself. In the anime he uses the name in public life, and uses "623" only in his radio show; his true identity is kept secret to the public. Unlike the other four Keronian/human child pairs, his relationship with Kururu is particularly distant, though they understand each other perfectly. Kururu may consider Mutsumi his only intellectual equal and vice versa, but he lives in his lab beneath the Hinata house instead of Mutsumi's home, thus shrouding Mutsumi's personal life in even more secrecy. However, Kururu seems aware of the fact that Mutsumi and Saburo are the same person. Mutsumi's name comes from a Japanese wordplay (Saburo means 326, and Mutsumi means 623). Mutsumi had previously appeared as a radio talk show for teens host in the anime Seven of Seven. Koyuki Azumaya Voiced by: Ryo Hirohashi (Japanese); Luci Christian (English, Funimation dub), Andrea Kwan (English, Animax Asia dub) is a kunoichi who entered Natsumi's school as a transfer student. Natsumi was her first deskmate at school. Drawn to Natsumi by what she only refers to as a "familiar scent", the girls soon become best friends. While she wears civilian clothing when in public, she always keeps on her ninja uniform in case of an emergency. Her skills as a civilian and a ninja are exceptionally outstanding: Her athletic ability rivals that of Natsumi, making her one of the most physically powerful character. Despite having amazing powers and a strict past, Koyuki is mostly carefree, optimistic, but in various occasions, eccentric. She believes in what is right and protects her friends with all her might. Unfortunately, her tendency to use her ninjitsu maneuvers to accomplish the most mundane of tasks often draws much unwanted attention. Having a huge crush on Natsumi,