Gonna be the Twin-Tail!!: Aika Tsube

Soji's childhood friend and an 15-year-old freshman at Yogetsu Private Academy. She treats Soji like a little brother and is rather overprotective of him although this is later discovered because of her massive crush on him despite not showing it to him. She is really good at martial arts thanks to her grandfather's training and later became Tail Blue in order to save Soji from being defeated. She always beat up Twoearle for her perversions. As Tail Blue, her main weapon is Spear of Water, Wave Lance which was upgraded to Eternal Chain. These are from Episodes 2 and 11.

Episode 2

Episode 11

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Gonna be the Twin-Tail!!: Twoearle

She's one of the main protagonists and the creator of the Tail Gear. She was also the original Tail Blue, but her efforts ended up dooming her homeworld as she was being played by the Ultimaguil by becoming a heroine to begin with after leaking information about their technology to her people. As the original Tail Blue, her twintails became popular and emulated by the people of her world, but this in turn just made her world even more of a target of the Ultimaguil. Before heading towards Earth, she had to give up her twin-tail hair style to make the Tail Red gear after her world lost all its attributes from the Ultimaguil as their food source. After meeting Soji (main protagonist) on Earth, she gave the Tail Red Gear to him in order for him to help her fight the Ultimaguil and prevent the Earth to suffer the same fate as her homeworld did. Later, she created two more Tail Gears: Tail Blue based on her original gear and Tail Yellow for Aika and Erina respectively, to help Soji out. She then transferred to Soji and Aika's school, Yōgetsu Private Academy, as an student and calls herself Sōji's relative since she lives with him afterwards. Because of her original abilities and twintails were lost in order to make the Tail Red gear, her fighting skills were gone as well, she then worked behind the scenes developing new Tail Gears after battles from Soji, Aika, and Erina, teleportation devices, and secret bases while being an supporter to the Twintail Warriors. She has feelings towards Soji later in the story and she enjoys teasing Aika with her large bust and perverted ways and often ends up getting grievously beaten up for it. Her personality can be very complex at times and also very seductive. Her actual age is unknown even though she claims to be the same age as Soji and Aika.