Onox's Castle

Northern Peak is a location in.

Features and Overview
The Northern Peak is a small mountain in northern Holodrum. It is located in the middle left hand side of Holodrum, seated between the Temple Remains and Tarm Ruins. The Northern Peak can only be accessed by one who bears all eight Essences of Nature and a Huge Maku Seed. At the top rests Onox's Castle.

Onox's Castle
Onox's Castle is the lair of Onox, the final or ante-penultimate boss of Oracle of Seasons. Link must use the Huge Maku Seed here to break the barrier. In the castle, Link fights a variety of enemies, including the mini-boss Facade. At the end, he fights Onox who has captured Din, the Oracle of Seasons. The entrance to the castle is guarded by Darknuts, Lynels, and a Ball and Chain Soldier.

Although pathways are open, seemingly to allow Link to bypass enemy fights, the enchanted area warps Link back to face the foes.