Rui Aoi is a characters in Ai Tenchi Muyo!.
Connection to Momotarō
New original characters in Ai Tenchi Muyo! are very loosely inspired by the popular Japanese folktale Momotarō. The Science Club seems to represent the monsters that plague the village.
Personality
Rui Aoi is timid and considerate but values her friendship with Yuki Fuka . She has an extreme fear of spiders and when confronted with one (or a fake one) she closes her eyes and becomes an uncontrollable destructive force as she attempts to escape or kill the spider.
Background
Her background before the series is unknown. Rui is the vice-president of the Junai Academy Science Club, The only other members being Yuki and Beni Kinojyou. They also utilize a large red robot named Goriki, which she treats as a cherished friend or pet.
The club been informed secretly by Washu of a "treasure" (Momo's Juraian ship) buried under the old school building and they have used all of the club's funds to excavate it from the caverns found there. She assists all of Yuki's schemes to get more funds from the School Council (other than beinghonest about what they would use them for).
After Momo and Beni's existence was effectively erased from the present timeline, it was shown that Yuki and Rui were still in the club, demanding funds to build their idea of a giant red robot.