Akura Saijini

Makoto's long-time friend. She is as opposite of a "proper girl" as it is possible for a young woman to be; she is foul-mouthed, extremely crass, and most notably, loves blasting massive farts in public. In spite of this, she is very caring and has a good sense of humor. 

 She figured out Makoto's fart fetish on her own, thanks to her psychology class, and she purposefully farts around him all the time, knowing it turns him on.