A state in which a Shade brings to bear the full power of his or her Artifact. This usually results in a physical transformation, sometimes into something far-removed from the human form.
Under non-taxing conditions, a Shade can remain Dark indefinitely, benefiting from the full range of powers afforded by his or her Artifact. Prolonged strenuous activity, activity that constantly requires an output up to the Artifact's rank, will temporarily exhaust the Artifact and the Shade will be forced back into his or her depowered state and will require rest.
Some psychics do not physically change when going Dark, but undergo some permanent change when first accepting their Artifacts into their bodies. This usually manifests as an alteration of the skin color.