|Japanese Name:||相生 祐子|
|Romanized Name:||Aioi Yūko|
|English Name:||Yuuko Aioi|
|First Appearance:||Episode 0|
|Affiliated:|| Mio Naganohara (Friend) |
Mai Minakami (Friend)
Nano Shinonome (Friend)
Mother Aioi (Mother)
|Japanese VA:||Mariko Honda|
Yuuko Aioi is an energetic high school girl with short brown hair. One of her negative sides is that she is often too lazy to do her own homework and always copies from either Mio or Mai. Her nickname is Yukko (ゆっこ).
Yuuko has pale, chestnut-brown hair, dark-umber eyes, and wears the schools standard girls uniform.
Yuuko loves making jokes and other people laugh, but often fails with her jokes or delivery. Yuuko is usually undeterred by her failures to crack jokes and is creative with coming up with new jokes or humorous reactions. Yuuko loves it when other people laugh at her jokes, but this is far and rare. She tends to be clumsy, and takes a simple-minded approach to life. She is not academically inclined, not diligent with her homework, and tends to fail tests. While she is generally an easygoing person, her mood changes instantly if she is insulted. She sometimes speaks Malay by greeting others with a selamat pagi which means good morning in both Malaysian and Indonesian language. Yuuko is show to have a fear of snakes.
Mio is the closest friend to Yuuko, but they are almost opposite in every way. This causes some tensions between them at times, but they usually appreciate each other's company. Even though Mio tends to be condescending and forgiving with her, some of Yuuko's actions occasionally (and almost always unintentionally) lead her to furious outbursts. Yuuko, on the other hand, is often prone to cheer up Mio and/or praise her for her qualities when the time comes. Mio sits in front of Yuuko in class.
Yuuko is usually oblivious to Mai. Whenever Yuuko tries to make Mai laugh, Mai responds nonchalantly. This causes Yuuko to try to make up for humor deficiencies. It is shown in the Manga that Yuuko has known Mai since middle school.
Nano is quite close to Yuuko, even though the latter isn't very smart. Yuuko's imagination was originally the only thing that led her to believe she was a robot because of the wind-up key on her back, but Yuuko only liked Nano more because of it: Indeed, she finds the fact that Nano is a robot to be amazing. Although she knows that Nano is a robot, she never tells anybody about it.
Thanks to her easygoing personality and love for robots and "cool things" in general, Yuuko obtains Hakase's friendship almost instantly as soon she enters the Shinonome Laboratory.
- Yuuko is persecuted by bad luck. This trait is occasionally emphasized by the appearance of a mysterious dog which puts his paw on her back trying to comfort her after a particular unfortunate event.
- Yuuko's "classroom dream" (which is some sort of mini-story that Yuuko dreams about when she falls asleep during classes) is the premise of Nichijou PSP video-game.
- When she was in Elementary School, Yuuko wanted to be a frilled necked lizard.
- Songs she performed: