From Destinypedia, the Destiny wiki
The Guardian is surrounded by Taken on all sides--the entire area is smothered in gray clouds and Taken Blights. The Guardian finds each of them and, despite heavy resistance from Taken, including Centurions and Captains, they manage to find and destroy all four blights.
Now with a waypoint set, the Guardian heads downstairs into the building and the area underground. Unsurprisingly, more Taken Thrall and Captains are lurking underneath. Assisted by Ghost's headlight, the Guardian eliminates them all. Suddenly, the entire basement goes completely dark, and the Guardian is Marked By the Void. The Ghost re-enters the Guardian, their light useless.
Using what little light they have, the Guardian eventually finds the Wizards hiding in separate parts of the basement. Zyrak and Mysik, the Daughters of Oryx, and Thyshik, Matron of Oryx are all located and killed. The Blight in The Steppes is lifted.