ON/OFF is a Japanese pop duo that is known for their distinctive vocal harmonies and dramatic compositions, which often blend modern pop elements with traditional Japanese musical motifs. The group is composed of twin brothers, Naoya and Kazuya Sakamoto, who debuted in the music industry in 2007. Their early work quickly caught attention due to their unique twin dynamic and their ability to infuse pop music with a sense of narrative and cultural depth influenced by their Japanese heritage.

Over the years, ON/OFF has cultivated a dedicated fan base through a catalog marked by its thematic consistency and evocative performances. Notable releases like "Legend of Twins I -双子伝説-" and its sequel "Legend of TwinsⅡ -続・双子伝説-" showcase not just their vocal talents but also their passion for storytelling, often drawing on folklore and legend to create a powerful, atmospheric sound. Songs such as "始まるのは、サヨナラ" and "Butterfly" reveal their range, from the profound to the exuberant, while tracks like "ふたつの鼓動と赤い罪" have cemented their place in the anime world, resonating with a broader international audience. The thoughtful lyrics and emotive melodies of ON/OFF continue to resonate with fans, carving out a unique niche for the duo in the landscape of Japanese pop music.