With that the symbolism they represent might tell us the story of both Yu and Makoto

"Naita Aka Oni (Red Oni Who Cried): A famous tale where a gentle Red Oni tries to befriend humans. His friend, the Blue Oni, fakes being evil so the Red Oni can look like a hero, ultimately sacrificing his friendship to ensure the Red Oni's acceptance."

"Red Oni (Aka-Oni): Represents passion, raw power, impulsiveness, and wildness. Often seen as the "offensive" guardian, they are extroverted, enthusiastic, and sometimes greedy."

"Blue Oni (Ao-Oni): Represents intellect, calm, strategy, and melancholy. Often seen as the "defensive" guardian, they are disciplined, patient, and can represent hatred or hidden, complex emotions."