Oniguma/Plot

Spirit Bear Arc
The Oniguma first appeared before Parona after she was captured by Hayase for helping March escape. It started by devouring the two Yanome guards nearby, and nearly crushed Parona, who narrowly escaped with her life. The bear appeared later at the sacrificial site, and almost managed to kill March and Parona both before being stopped by Fushi, whose immortality allowed him to subdue the massive beast. It was then brought to Yanome to be dismantled, where it was left under March's care before dying peacefully. Thus, the immortal acquired its form, while its spirit continued to follow him.

New World Arc
400 years after the battle for Renril, with the Nokkers defeated and the world in presumed peace, Fushi resurrected his past companions, including the Oniguma, enlisting his help in partially demolishing the house he was staying at in order to expand it.