Mizuchi is a large dragon-like demon who was encased in ice within Orochi's Ice Room. He is the guardian of the Mystic Amber. In the past, Mizuchi was the protector of a seaside village before he defected to Orochi when the village was razed in a war. During the process, he abandoned hope for mankind. He then froze himself, becoming the eternal protector of the Mystic Amber, until he smelled the scent of Chibiterasu and Manpuku and broke free of his icy state to devour them.
When battling Mizuchi, it is important to note the icicles over his head. The player must attack the demon encased in ice and once he is dizzy or stunned, an icicle will appear to almost fall. The player must powerslash that icicle and run towards the end of the room quickly and load Manpuku inside the cannon or else the giant dragon will break free from its hold. Using Manpuku's fire abilities will allow the player to light the cannon, sending Manpuku towards the demons head and dealing alot of damage. Once the player deals a significant amount of damage, the demon will begin to put up an ice barrier when shooting Manpuku from the cannon. Simply melt the barrier with Manpuku's hair or draw the infinity sign for fireburst to continue on with the attack. Once the player defeats Mizuchi, Chibiterasu is able to free Shiranui and Ishaku from there cold encasement and have a nice family reunion before setting out to Orochi's cave in place of him.
- The Mystic Amber serves the same purpose to the game as the Serpent Crystal from Ōkami. There may be some connection between them as they both provide the means for entry to the Moon Cave by dispelling the barrier.