She's the armored girl Asuka, Tobimaro's younger sister who has the unusual combination of being as timid as a mouse and having the power of a locomotive.

Asuka inherited her mother's superhuman strength, speed and agility but is a meek and quiet girl with a childlike mind. Her mother had her raised in isolation from men. Her brother never knew of her existence and she didn't even know what a brother was. The first man she ever set eyes on was, Ataru as he ambushed her. The experience left her with a really bad impression of men and now she has a dangerous phobia of males. From then on the mere sight of a man will send her into a frightened rampage causing massive destruction and swatting away all of those scary men.

It turns out that her parents had arranged a marriage between her and Shuutarou Mendou to unite the two families. This came as a total surprise to Mendou. The first time he laid eyes on her, all he saw of her was a figure in a hulking and fearsome black armor. Asuka likes to wear this tank-like armor because it makes her feel safe, but it doesn't make her very desirable. The thought of marrying a big tin-can didn't sit well with Mendou so he tried to squirm out of the arrangement. But when Lum hit the armor with her lightning bolts, it collapsed revealing a beautiful maiden underneath.

As soon as he saw her true appearance, it happened. For the first time ever after years of leading girls on, Mendou actually fell victim to love at first sight. All of the sudden he was very motivated to marry Asuka. Mendou began fighting over her with Ataru and this really frightened Asuka. But her brother Tobimaro nobly defended her repeatedly against the two lechers. Strangely enough because he had come to the rescue, Asuka fell in love with her own brother, who she had never seen before that day.

Poor, innocent Asuka has a very mixed-up view of males. Asuka doesn't understand how male-female relationships are supposed to work. She'll often trying to sleep with and take baths with her brother, not knowing what a huge taboo it is. To her there are two kinds of men; Men that frighten her and onii-san (big brothers) which is how Asuka now sees Tobimaro, Mendou and Ryuunosuke. Not to say that they don't take their share of beatings from her. Being loved by Asuka is perhaps more dangerous than scaring her because one hug from her can crush a man's spine. Asuka's mother tries everything to cure her girl of her phobia. But everytime Asuka takes a step towards getting over her fear, along comes Ataru who triggers a relapse.

Just like her mother and brother, Asuka has starry eyes.