Arkborn

The Arkborn are an alien species and members of the Cabal Loyalist Faction under Emperor Calus in Destiny 2.

Physiology
The Arkborn are said to be Arc-based creatures, meaning they are made of electrical energy. In their natural state in they exist in vast arks, vessels that surpass even the Worldeater, The Leviathan.

History
During his time of exile, Emperor Calus encountered the Arkborn aboard the Leviathan. He posed a threat to the Arkborn's installer conduits, and to keep him away, one of their number agreed to become his Shadow.

Source

 * Cabal Booklet
 * Destiny 2