Vortex

Description from Elona
The swirling Vortex, unleashed by the death of Varesh Ossa, leads to the Realm of Torment

Description from Realm of Torment
The Vortex leads back to the mortal realm.

What it Does
Basically, the vortex just lets players travel between the Mortal Realm and the Realm of Torment much like the boat icon that allows you to travel between continents.