BiS is a Japanese alternative idol group known for a punk and rock-infused sound that often critiques the mainstream idol industry. Short for Brand-new idol Society, the group was founded in 2010 by its leader, Pour Lui, and has since become known for its provocative and musically aggressive style. Over its history, BiS has undergone multiple lineup changes and a temporary disbandment, but it remains a significant act within the alternative idol scene, which prioritizes raw energy and genre experimentation over traditional pop polish.

The musical identity of BiS incorporates elements of punk, metal, ska, and shoegaze, a blend that helped them gain a reputation as alternative idols distinct from mainstream groups. This approach is consistent across their anime-related work. In 2019, the group released the single Are you ready?, which served as the ending theme for the television anime Yu-Gi-Oh! VRAINS. The single, which also includes the B-side track BiSBiS, was released on March 20, 2019, by Nippon Crown. The title track is noted for its extended eleven-minute runtime and creative inspiration drawn from the Queen biopic Bohemian Rhapsody.

BiS is also credited for the song primal., which is connected to the anime series Backstage Idol Story. The single STUPiG, released in an anime edition, includes a DVD featuring episodes of Backstage Idol Story as bonus content, directly linking the group's music to that animated work. The group has been active under the WACK music production company, which manages several idol groups and facilitates a distinct, often abrasive, visual and sonic aesthetic. Through these credits, BiS has established a presence in the anime music sector, bringing its unconventional and rebellious musical style to soundtrack and theme song work.