This book is a Kamito x Hinano Tachibana (KamiHina) doujin manga. The story's setting is a world line where "The magical girl Hinano-chan changed her appearance (to look younger) using magic to draw Kamito-san's interest". (Source: Melonbooks) An OreApo doujin manga featuring the independent Vtuber Kamito ("Oreo") and the Virtual eSports Project! Vtuber Hinano Tachibana ("Apollo").