Youko Takahashi is the Head Teacher of Year 2 and the homeroom teacher of class A. She is bespectacled, probably the smartest person in Fumizuki, but is really bad at baseball. Her total score on all subjects is 7800, nearly twice as much as Shouko. Her Shoukanjuu is clad in black military uniform and armed with a whip.
He and his girlfriend Rico are Yuji and Shouko's rivals in the wedding competition in episode 7.
Aoi Kogure is a female student of class 3-A at Fumizuki Academy. She speaks in a polite manner and uses "watakushi" to refer to herself. She's also a member of the Tea Ceremony Club and the Rhythmic Gymnastics Club. According to Akihisa Yoshii, she's a Japanese beauty who looks good in kimono, close to Shouko's type. She has bewitching atmosphere and big breasts, and her every gesture is sensual. Kouta Tsuchiya is very weak to Kogure's appearance, it often makes Aiko Kudou jealous. She appeared for the first time in the test of courage tournament wearing a gymnastics leotard to show her good figure off, dropping almost every 2nd year male students off due to their nosebleed, including Kouta. In the war of Class 2-F against Class 2-C, she helped class 2-C's class representative, Yuuka Koyama, with her strategies as Koyama is her junior in the Tea Ceremony Club. Later, in the final war of 2nd year students vs 3rd year students, she used her erotic appearance to weaken Kouta and drove him to the verge of death.
Tohru Kurosaki is a student in Class 2-C in Fumizuki Academy. His Summoned Being wears the same turban, jacket, and pants as the generic Class 2-C Beings and wields a scimitar.
A Chemistry teacher in Fumizuki Academy.
She is an A class student and is especially good in health. In episode 2, she fights against Kouta and loses. She also likes to pick on Kouta's ability to handle girls by talking about her underwear and bra. She does this in episode 19 when the summoners avatars are saying their secrets. She also abused this in episode 16, which was easy for her to do because she was swimming at the beach with the rest of the main characters.
The most mysterious of the Gung-Ho Guns. His portrayal in both the anime and manga are drastically different. In the anime, Zazie uses the identity of a young boy named "Beeb" as a disguise. He can control sand-worms with a high-frequency device he wears on his head. The anime never exactly gives a clear explanation as to what Zazie was. It can be theorized that Zazie was a malevolent entity that took control of the boy whenever it needed to, that he was in fact a much older man who only looked like a young boy, or that he was actually a child assassin driven to the brink of insanity by his association with the Guns. In the manga... his body is controlled by a collective of group-minded insects. These insects are the original inhabitants of the planet Gunsmoke and have formed an alliance with Knives to see whether humans or Plants are better to co-exist with. The insects that form Zazie also seem to represent the planet's consciousness, as represented by the sandworms he can control as well (Zazie has been referred to as the 'leader of the sandworms' by Knives). His body is destroyed by Hoppered for spying on him and Midvalley. Zazie later reappears in the body of a teenage girl. In Trigun Maximum 11 this body is destroyed as well after trying to implant an insect in Knives to control him. Zazie reappears one last time as an odd-looking man in disco-clothing in order to deliver his coin to Vash. It is revealed that these bodies are human, but are controlled by a small worm-like creature that lives inside it, similar to the one Zazie tried to implant in Knives. When the hive is destroyed by Knives, the man spits out the creature and has no memories of his time as host to Zazie. His Gung-Ho Gun number is 12 in the manga, and 4 in the anime. (Source: Wikipedia)