Uran

 is Atom's little sister in all of his appearances and have different versions according to the series which she appeared in, though still have some of her basic traits.

Story
 was created by Dr. Ochanomizu in the new years eve and was intended to be given to Atom as a gift for his hardwork in the following year.

Uran just after being activated started to dance and later was introduced to her parents, but she don't knew any social skills, mainly due the fact Dr. Ochanomizu didin't got time to train her.

After chasing a plane and running outside, Uran was followed by her brother to the city.

Atom tried to teach Uran how things works, but she refused to listen and left him. Later, she was caught by a gang who steal child robots in order to convert them into robot slaves. Atom was scolded by his teacher, Shunsaku Ban (a.k.a Higeoyaji) for abandoning his newly born sister and was tould to bring her back.

However, he could not find any clue of were she was and then upon receiving a phone call from Dr. Ochanomizu, he was alerted about the robot smuggling gang and gone to search the sea.

Uran escaped from her prison cell alongside the other robot children and saw Atom in a video flying and she screamed his name, this made Atom confused since he wasn't able to see where the sound was coming from. Then, Uran who was attacked by the security guards for refusing to surrender ended up disabling the stealth system of the Island and was them saved by her brother who foiled the plans of the robot smuggling gang.

After living with Atom, Uran learned to respect and idolatre him.

However, people alike started to mock Uran for not being so advanced as her older brother and with her pride hurt, she goes in a journey to prove that 100.000 horsepower, built in weapons and jets are not everything for a robot.