Runa looks like a high school girl wearing a cardigan and sailor suit. She has long hair with braids tied into circles on the sides of her head before they flowed down her back.
Runa always appears confident and proud, with her alluring voice one of her undeniable qualities due to the ability she got from the Otherside, though Sorawo mentions she has a bit of a stutter. It was her obssession with Satsuki that is prevalent throughout, despite never even meeting her, and would do anything for her. She went as far as forming a cult, who she calls her fans, kidnapping Kozakura and Sorawo (the cultists mistaking her for Toriko), and attack DS Lab during File 11, Volume 3.
Runa Urumi is a streamer since middle school, but wasn't as popular despite her best efforts. Just when she was about to give up, she found a video titled 'Blue World' while listening to ASMR videos. Watching the video, she claimed to have seen Satsuki appeared and bestowed her a gift from the Blue World, which allows her to brainwash people and do her bidding. She became obsessed with Satsuki, believing that her life was meant to worship Satsuki.