Umbrakinesis

Umbrakinesis or Sciakinesis is the ability to mentally generate and manipulate darkness, deactivated photons mostly in the absence of light. One with this ability can even deactivate and repulse or travel through shadows (see Shadow Travel) by converting deactivated photons into a dark version of a portal.

The Battle of the Labyrinth
After the battle, Nico walks into the woods and Percy follows him. Nico tells Percy he has to investigate his past. As Nico walks away, Percy states that the shadows of the forest were reaching out to Nico as if they were embracing him.

The Last Olympian
Nico shows that he is able to Shadow Travel, the ability to travel through darkness. Most Underworld creatures are also able to do this, as shown by Mrs. O'Leary's ability to do the same.

Abilities

 * Surround enemies into lightless space.
 * Use darkness to create portals to travel from one place to the next (Shadow Travel).
 * Use shadows to cover oneself in darkness to become invisible.
 * Possibly see through darkness while your enemies cannot.
 * Able to use black energy to create barriers. Hades was even able to block Zeus' Master Bolt.

Users of Umbrakinesis

 * Hades
 * Persephone
 * Nyx
 * Erebos
 * Nico di Angelo
 * Mrs. O'Leary
 * Underworld creatures