Verok is inprisoned. You see her in the Crucible Map: The Dungeons. That is why there is a big crystal in the center of the map, and in that crystal you see a hive Wizard, but it looks completely different to a regular Wizard, it is much more ceremonial and scary than the regular spawn of Crota. Also, I am pretty sure that Eris states that Verok was imprisoned, and this is the most obvious place where she would be. Rifle Gaming just did a video on how to get out of the map on The Dungeons and look clearly at what lies inside of the Crystal. Otherwise, you can see the outline of Verok if you look at the Crystal from the outside. Look into this?