Aoi Matataku, also known as Otome Blue (乙女ブルー Otome Burū), is one of the main characters in Houkago Sentai Otome Rangers. Aoi is a funny and cheerful girl and is great when it comes down to drawing. Hiromi relies on her the most, even if Aoi interrupts her a lot when she is speaking and tends to find crazy the things that Hiromi says.
Aoi may seem to be a carefree person, bit in fact, she is very relible and can make friends with almost anyone, even with a villain, which makes her friends surprised. However, most of the times, she isn't a serious girl and often acts funny, impatient and keeps being cheerful and optimistic when she and her friends are in a trouble or doubtful about something, thus always tries to find a way too calm down others whever it's needed. Hiromi and Amami find it great, but that is very annoying for Rin.
- Aoi's voice actress Tomoyo Kurosawa also voiced Otome Arisugawa from Aikatsu!. Coincidentally, the word "otome" is the part of the title of Houkago Sentai Otome Rangers and the part of Aoi's alter ego Otome Blue.