Aoi Matsubara (松原 葵 Matsubara Aoi) a girl who is a practitioner at martial arts.
Aoi has short dark blue hair, light blue eyes and an average height.
Aoi has a very determined personality who loves the martial arts termed as Extreme Rules.
- The name Aoi means "hollyhock, althea" (葵).
- Aoi's surname Matsubara means "pine tree, fir tree" (松) (matsu) and "field, plain" (原) (hara/bara).
- There have been a few hints that Aoi may like Hiroyuki Fujita.
- Aoi idolizes Ayaka Kurusugawa who is her rival at Extreme Rules martial arts.