Koarai appeared alongside Haruaki Azuma and Tsuneyuki Okudera as one of the B-rank teams taking care of trion soldiers. He helped defeat several regular trion soldiers. When a rabbit appeared and knocked away Okudera, Koarai charged the rabbit. Azuma shouted at him to get back, but he ignored the orders. The rabbit caught him easily. Koarai attempted to cut his way to breedom, but the Rabbit tore off his arms.
The Rabbit’s chest plates began to open, and Koarai panicked, calling out for Azuma. Azuma attempted to shoot down the Rabbit, but was unable to do so. Azuma instead shot his head off, forcing him to bail out.