Nabekane Tsubasa

Mikado's younger sister and the sisters Neneko and Arisu's childhood friend. Since they were children Mikado has wanted to create a Mecha-con and marry many girls and make them all happy. She approves of his desire and wants to help him create a harem so long as she's a part of it. A super genius she creates an invention called 'Pandora' that is supposed to help him learn information from the internet although it doesn't work as planned. Hates going to school, hates wearing clothing even outside, and loves penguins. Sometimes wanders town in a Penguin suit.

Term of endearment for her husband 'darling'.