Be prepared to sink in some time acquiring the Minor Relics of Energy from the Forlorns. They don't always dropped the one you need and some times don't spawn at all. I had gone through about 6 rounds of killing undead in the pit just to get 1 or 2 Forlorns to spawn. Sometimes I was lucky and had 3 Forlorns up, other times just the non-name. It's about a 20-25 min respawn timer for these npcs. Suv and Nep seem to be the common drops.
Get the message this mob see can you etc etc with regular invis and do not get the message with Improved invis but she sees through it anyway just something to note.