|"You four have merely scratched the surface of your full potential."
Deepstone is a deep black aquatic material that is mined from the bottom of the Endless Sea in the world of Ninjago. The molecules that Deepstone consists of are constantly moving, yet still staying solid; making it an effective material for utilization in both combat and defense against ghosts, since it has the same effect on ghosts as Vengestone does on the Elemental Masters.
One of its uses is to forge Aeroblades, a shuriken-like weapon that is highly effective against ghosts. It was also forged into armor, along with vehicles, for the ninja to aid them in their fight against the Preeminent.
- Black katanas, referred to as Deepstone Katanas, were used by the ninja and Ronin in the Possession sets.
- Deepstone is fairly similar to Vengestone, as they are both able to prevent ghosts from phasing through them.