Vurok

Vurok, Eir Spawn is a Hive Wizard encountered in the Temple of Crota, in the Ocean of Storms on the Moon in "The Dark Beyond" Story Mission avaliable in the Beta prior to initial release. He attacks using an enemy specific unique ability called Darkness Blast that deals Arc Damage, and has an elemental shield with a vulnerability to fire, like all Hive Wizards seem to possess thus far.

Vurok seems to share the traditional Wizard ability to emit a black cloud of mist that can impair a player's line of sight and poison them temporarily.

Trivia

 * (SPECULATION) It is entirely possible that Voruk is simply a repurposed Gotra, Eir Spawn from the Alpha. Voruk's character model has the same facial piercing and armor design that Gotra had, and likewise shared many of his abilities.
 * (SPECULATION) Gotra is from a faction known as "The Hidden Swarm". This could possibly be the name of the Hive Faction taking up residence on the Moon. Considering the plot points uncovered at the end of this mission by your Ghost, it seems an apt name.