MY FIRST STORY is a Japanese rock band formed in Shibuya, Tokyo, in 2011. Fronted by vocalist Hiroki Moriuchi (Hiro)—the younger brother of Taka—the band quickly gained recognition in Japan's alternative and post-hardcore scene. Their music blends emotional melodies with heavy rock elements, drawing comparisons to ONE OK ROCK while carving out their own distinct identity. Over the years, MY FIRST STORY has built a dedicated fanbase through intense live performances and albums such as THE STORY IS MY LIFE, ANTITHESE, and S・S・S.

The most notable collaboration between the two bands took place on November 14, 2023, when ONE OK ROCK and MY FIRST STORY co-headlined the special concert "VS" at Tokyo Dome, a historic moment that brought the two brother-led bands together on one of Japan's biggest stages. Additionally, Hiro joined ONE OK ROCK at 1CHANCE FESTIVAL 2022 in Kumamoto, performing alongside Taka highlighting the unique family and musical bond between the groups.