" I may not be suited for a big bust sized Tail Gear, but it's not worth Soji losing their life over something like that . . . . gimme that blue bracelet !!! "



Aika Tsube (津辺 愛香? Tsube Aika) / Tail Blue (テイルブルー? Teiru Burū)
Both Aika and TailBlue are voiced by: Yūka Aisaka
(Japanese); Sarah Wiedenheft (English)



Aika is about the same height as Soji, medium body with a slightly thinner body build, due to her being very athletic. She has a slightly angular face, with a slightly pointed chin. Aika has very long dark blue hair, that she has always worn in the twin tail hairstyle. She has deep set anime girl 'big eyes', with a reddish-maroon color. Her skin tone is beige with a faint pinkish color, and with a very even texture overall. Unfortunately, although she has a very attractive appearance, Aika has over time developed a complex dysphoria with the look and shape of her body, especially with her flat, underdeveloped chest. Refusing to wear a padded bra, she opts for wearing a training bra, or a sports bra. She is quite sensitive about her small bust size and shape, and is quick to take offense at any mention or hint of it. However, her school uniform's mini-skirt shows off her long, thin legs.

Most often seen at school, Akia wears the female school uniform. This consisting of a white blouse with a fluffy powder blue bow tie, an attached black pleated mini-skirt, a beige with black trim ladies business jacket, and black thigh-high stockings with black oxford shoes. For casual wear, Aika typically wears a T-shirt with denim booty shorts, and thigh-high stockings, or bare legs, and athletic shoes. Sometimes she will wear a pretty dress, which will make her look like a little girl. Despite Aika's feminine dress and grooming, If it wasn't for her long, blue twin tails, many humans and Elemelians would often mistake her for an adolescent, abet feminine, teenage boy. This she takes in stride, not worrying about what others think of her or her appearance.


One of the heroines of the Twin Tails, Aika is a 15-year-old freshman of Yōgetsu Private Academy, and a best friend of Sōji since childhood. Due to her overprotective nature, she treats Sōji like a errant little brother, and is rather fond of him. Although occurring after her puberty, it is later revealed that she acted such because of her massive romantic crush on him. Aika has complex dysphoria with the look and shape of her body. However, she does not have anorexia, and is able to control her wellbeing and mental health.
She can, at times, have a violent, abrasive attitude, especially toward Twoearle, who often teases her about her small, childlike chest. Aika is sharp and quick. both mentally and physically. and can almost always 'get the better of' Soji in whatever they are doing together. She is quite intelligent, and does well in school acdemically, as well as in PE. She can defend herself in almost any situation with rock-hard fearlessness, as she has been trained in the Martial Arts by her Grandfather. Aika is generious, and will help out if she can whenever she sees others in distress. She lives next door to Soji and Soji's mother, and likes to climb out of the window of her second story bedroom, leap across the gap to the roof, and surprise Soji by entering his bedroom through the upper window.