Kroi is a Japanese five-member band formed in February 2018. The group began when middle-school classmates 内田怜央 and 長谷部悠生 connected with university classmates 関将典 and 益田英知 through Instagram direct messages. 千葉大樹 joined on keyboards in December 2019, establishing the current lineup. Their name refers to the idea that mixing every color produces black, reflecting a style that blends funk rock, j-pop, and other genres.
Kroi made its recorded debut with the digital single "Suck a Lemmon" in October 2018. In 2019, the band appeared at SUMMER SONIC 2019 and released the EP Polyester and the single "Fire Brain". After the EP hub in 2020, Kroi announced its major debut with Pony Canyon's IRORI Records in 2021 and released its first album LENS; later that year, it followed with the EP nerd. The band's later releases include the second album Telegraph in 2022 and the EP MAGNET in 2023. In anime-related work, Kroi performed "SPIN", the OP of "JoJo's Bizarre Adventure".
