BTS created the BT21 characters, each representing a different member of the group. One of the most beloved BT21 characters is Koya, a cute blue koala with a calm and intelligent demeanor. Koya's character is often seen with books, symbolizing wisdom, knowledge, and intellectual curiosity. Koya's affinity for books encourages K-Pop fans to embrace the joy of reading and the pursuit of knowledge. A fanart K-Pop sticker with BTS BT21 Koya and Books Sticker.