|Manga Debut||Volume 3, Chapter 11|
|Anime Debut||Season 2, Episode 12: Summer Festival!|
BCS is a band consisting of at least four members.
The band seems to be fairly skilled and famous, able to perform in a gigantic musical festival as the "Natsu Rock Festival" (which is most likely an allusion to the Fuji Rock Festival, the largest outdoor music event in whole Japan), where they could enthuse a crowd of many thousands of people with their music.
The band's music is Punk Rock, which can be heard in their song "Rule".