Ikkyu  

, 一旧

The individual who claims to be Nozomu Itoshiki's old friend, despite not actually being so. They share a similar interest in old things as Nozomu does. Their name is referenced in the anime series Ikkyū-san. This person attempted to marry Rin and, by doing so, gained an "old name" and became part of an "old family." However, Kafuka prevented them from succeeding in their pursuit of marriage with Rin.