Mayoi Ayase is often called a phantom due to his "incorporeal" presence around Yumenosaki Academy and the Ensemble Square building, as he would shroud his presence by hiding in the ceiling, walls, and other various hidden passageways. Prior to attending Yumenosaki Academy, Mayoi Ayase would frequent the academy and watch struggling students lacking skill practice late into the night. Moved by their efforts, he would help the idols out or leave advice through a mysterious letter, earning a reputation as one of the Seven Mysterious Yumenosaki as a "phantom".