You had a vision of the Eye, which once belonged to one of the Shadow Overlords, who got since overthrown. Overlord's mind is still alive in this artifact, making it as dangerous as it is powerful.
A Gal who deals damage while wielding the Eye, replenishes her TU, Energy and HP (Mind effect). However, this malevolent entity will drain life force every turn (-2 HP, +3 Stun and some extra Stun when dealing damage) and whisper all sorts of nasty things (-2 Morale). All Mind damage taken is reduced by 2/3.
Now the Eye is in the possession of an unknown, powerful entity, and we don't even know where to search for it.
Maybe it's for the best.