Agate Mountain is the mountain underneath which Darkstalker was trapped for about 2,000 years. It was the tallest mountain in Pyrrhia before an earthquake created a landslide and part of it collapsed, leaving Jade Mountain as the new tallest mountain on the continent and waking Darkstalker by snapping the moonstone bracelet. This was envisioned by Clearsight when she contemplated her futures. This mountain is in the Claws of the Clouds Mountain range, within sight of Jade Mountain Academy as demonstrated in Escaping Peril and is stated in Darkstalker (Legends).
- An agate is a cryptocrystalline variety of silica, chiefly chalcedony that consist of a large variety of colors and types.
- It is possible that all of the mountains in the Claws of the Clouds range are named after gems.
- Agate Mountain isn't in the Darkstalker (Legends) map, despite it being the tallest mountain in that time period.
- It is likely that the fall of Agate Mountain caused the disappearance of most of the old NightWing Kingdom coast.