Rui Osano/Plot

Background
Osano was a fashion model until middle school, when she got bored and left the talent agency. She joined Border approximately three years before Chika Amatori and Yūma Kuga.

Introduction Arc
Suwa Squad presumably takes part in the extermination of all Rads in Mikado City.

Large-Scale Invasion Arc
Osano assists her teammates during the Second Large-Scale Invasion. She activates Starmaker when Kōtarō Suwa and Daichi Tsutsumi hit the shell containing Enedora's vitals. After the end of the invasion, Suwa Squad was the recipient of an Excellent Distinguished Service award.

Round Two
On February 2, three days before their match against Tamakoma Second and Arafune Squad, the members of Suwa Squad gather to prepare a strategy in HQ's cafeteria. Osano states that she has never heard of any of the agents of Tamakoma Second. When Hisato Sasamori shows his teammates the footage of Tamakoma Second's first rank war, she remarks that Chika and Yūma look very young. Three days later, when Tamakoma Second's map of choice is revealed to be Cityscape C, all of Suwa Squad is taken aback. Osano observes that since the spawn points are random, they still have a chance. Tsutsumi apologizes to her when he bails out, but she tells him not to worry since he scored a point. When the match is over, she chides Suwa for having failed to defeat a single opponent while Tsutsumi and Sasamori both did.

Galopoula's Blitz
On the night of February 19 Osano presumably assisted her teammates during Galopoula's Invasion.