A female mercenary who has a difficult personality and notorious for using violence against employers she dislikes. She has a good eye when it comes to others, and at a glance notices Lloyd's strength and plans to use his power to make money. She is also known as the "One-Armed Mercenary."
Riho generally gives off an intimidating aura, a sly grin plastered to her face with darkness looming in her eyes, at least when she is not threatened. Her prosthetic arm is of white metal with blue accents. It has decorative wings atop her bicep. It is elegant yet capable of unprecedented damage.
Actively looking for opportunities to make money, Riho is often sizing up anyone and everyone to deem whether or not they can be of use to her. That alone can provoke the question if she is selfish, greedy, and shallow. However, she is undeniably perceptive.
Riho Flavin (リホフラビン, rihofurabin ), a play on the vitamin B2, riboflavin (リボフラビン, ribofurabin ).
Voiced by: Kimiko Koyama (Japanese), Larissa Wolcott (English) The creative arts teacher, Uzuki acts like a small girl and is very happy-go-lucky. She gets into many arguments with Satsuki and is often seen wearing angel-like wings due to her obsession with cosplay.
Voiced by: Kahoru Sasajima (Japanese), Lee Eddy (English) The athletics coach, Satsuki prefers brawn over brains and has a loud personality. A tomboy, she is seen as very aggressive and violent, acting or speaking without thinking things through, but with a very sweet personality underneath.
It was adapted into a five-part OVA series in 2001; a thirteen-episode animated TV series in 2002; a sequel TV series, called Happy Lesson Advance, in 2003; and a second OVA series, Happy Lesson: The Final, in 2004. The series has also been adapted into a series of drama CDs and a Dreamcast game.
She is seen wearing a Japanese priest dress and puts her sword against Chitose's neck in order to attain a positive response.
In the end of Happy Lesson Advance she admits that she likes Chitose. Kanna Togakushi (十隠 カンナ, Togakushi Kanna) Voiced by: Akiko Nakagawa (Japane se), Carla Witt (English) Kisaragi's childhood friend.
She is actually an alien , which explains her high technological skills.