Just throwing this out there for discussion... The Obelisk of Lost Souls (Note the name) was a portal between the void and Norrath but the rituals in OOLS also took the spirits of vessels on Norrath, condemnded them to the Ethernere, and then placed Shadowmen in the vessels. And since the Ethernere has connections to other planes, it stands to reason that there is a portal in the Ethernere that goes to the void. Everling tried to travel to the Ethernere to recover his daughters only to find that he was in the void. What's the connection between the two planes?