Ririn

is an (anime only Modified Soul, created by Kisuke Urahara to serve as a Bount detector.

Character Outline
Ririn, while in her gigai form, is a small girl with short blonde hair wearing a pink, fur-trimmed coat, a purple bird-shaped cape, and red boots. When not in her gigai', she inhabits an anthropomorphic bird plushie. Her special ability is the creation of illusions. She acts as the leader of the trio (herself Noba Kurōdo), and has a fondness for games. She is partnered with Ichigo Kurosaki. At first she disliked Ichigo due to their conflicting personalities, but now she has grown to be very fond of him, even becoming at times extremely jealous of Rukia Kuchiki's close relationship with Ichigo. She can be petty and arrogant at times, but she shows real concern for her friends. She has stepped into harm's way more than a few times to help save Ichigo, Rukia, Kon, and others. She often looks down on Kon as inferior, which causes frequent arguments between the two.

Synopsis
She is first introduced at that begining of the Bount arc and serves as an antagonist until revealed that she was creaated by Kisuke Urahara to test Ichigo and his friends.