Pero appears as a dog with a robust frame and a light-colored coat. Its appearance closely resembles a dog from the Shiba Inu breed.
Toaru Kagaku no Railgun
Dream Ranker Arc
- Main article: Dream Ranker Arc
Pero is introduced as Miyama Shaei's companion whenever the boy feels ostracized by his classmates. Eventually, Shaei and Pero become familiar with each other, with Pero forming a sort of bond with him while Shaei turns him into a confidante of sorts regarding his personal problems. This continued even as Shaei transferred schools.
Eventually, Pero shows up in Shaei's predictions, where the dog is surrounded by fire. In his desperation to save what he considers his only friend, Shaei asks help from Shirai Kuroko, who has shown to have the ability to overturn his predictions. At the appointed day of the incident involving Pero, the dog is saved by Kuroko.