At one point, Ayato and Yuki were best friends who attended school together on a regular basis. However, their relationship took a dark turn when Yuki disclosed her desire to consume "the human soul," prompting Ayato to take a stand and vow to defeat her. Despite engaging in a fierce battle to stop her evil plot, they acted as though nothing had happened the following day. The reality of the situation felt like a dream, as they resumed their ordinary routine.