"Rio" is the main vocalist of the music unit "WHITEBOX" which is popular on SNS, "Kopi" is active in a wide range of activities such as singer, actor, talent, YouTuber, and is also active as an artist himself. It is a collaboration song with the beat makeup of "stb". "Monster and Girl" is a song that depicts the story of two people who have received much slander and slander, meet and confront the world. He had a complex about his appearance and compared himself to a monster because he was only concerned about the eyes around her. He compares the important person who saved him from that suffering to a girl. Also, the girl had a similar past of suffering from loneliness, and was saved by a monster who was by her side. This is a love song in which these two people look for a future where they can snuggle up and laugh together, vowing to live forever.