Not going to tell him much, Daan? But you told him exactly how to defeat the Empathic Manifestation!
Teodulo, in any case, once you've spoken with a very, very weak god, note down exactly the instructions he gives. That goes for the blind rebel priest, too: heed what he says.
Here's one important hint that doesn't require a spoiler tab: only your PC can wield the weapon against the creature. I discovered this after sending Korgan in with the thing, but as soon as the Eye was found, it zapped back to my character. So whomever you use to challenge the various baddies underground, keep your character within, say, fifty feet with a pair of boots of haste handy (though unworn).