Local Enemy Bestiary
Once you enter the area, go north to the main falls. Shadow will now leave. Head over to the ledge now, and, when prompted, suicidally jump off. On the way down, you’ll fight groups of Opinicus Fish. After sixty seconds after the first encounter and finish off the current group, you’ll fight the Rhizopas. So, yes, stick with the first group of Opinicus Fish for about sixty seconds and keep your HP near max.
Once time’s up, kill the fish and fight the Rhizopas by using the Aura Cannon Blitz and Cyan’s #1/#4 Bushidos.