Opening the Portal
With Tanval's help, we've lowered the final ward guarding the prison of Sadal, the Brother of Strife. The mages who originally imprisioned Sadal linger on the Tormented Spire as spirits, angered by Tanval's ritual.
Collect Focus Stone of Flame
The spirit Arch-Mage Genvis Faledran informed me that three Focus Stones are required to open Sadal's prison. The first Focus Stone is on the south side of the caldera. I must cross a pit of molten lava to reach it.
Speak with Mavos Siloreth
I must complete one final trial. I'll find the third spirit near a cave above the caldera.
Place Focus Stone of Flame, Wrath and Binding
The spirit magi have agreed to help me. I need to place the three Focus Stones in the center of the caldera.
— game journal