From Guild Wars 2 Wiki
Ether Towers are ancient defensive towers built by the mursaat and placed throughout their fortresses such as Caliph's Steps. They are known to entrap souls, though the reason is unknown, and emit powerful magic which attracts eidolons.
- Defeat jade constructs and destroy other mursaat defenses (80) [Group Event]
- Approaching an Ether Tower will prompt it to use Spectral Agony on the player and create an area of effect around it that will slow attacks made from within it, but does not cause Slow and cannot be removed.