Gucchan

"Gucchan" is the best friend of Komaki at the start of the story. As it's hinted, she always liked Takayama and when Komaki will deny his will to bring their love relationship to another level will be the one that will sleep with him. Komaki, thanks to her new ability, will soon realize the betrayal of the friend and will break the friendship with her (and Takayama as well). Gucchan's real name was never revealed and always only been called Gucchan by the friend Komaki. It's let understanding that she becomes Takayama's new girlfriend.