Yuri Otani is an average, quiet and melancholic girl who is trying to live a normal life. She is 12 years old. She is easily frightened and is a crybaby, whether scared or happy. She hates aliens, finding them scary and disgusting. Yuri was voted by her sixth grade classmates to begrudgingly join the Alien Party. Its a team that captures any aliens wandering on school grounds. She is known as the weak link in the group. Her team's equipment are rollerblades, nets, pads and dart guns. She is very reluctant to merge with her Borg.

However, her friends inspire her her to carry on and learn from each other and themselves. Despite her fears, Yuri has the potential to keep on fighting. She is also good friends with Miyu Tamaki.