Post-MSQ cutscene:

Seeing Zenos be back makes me immediately think that this is some Ascian nonsense with Elidibus, but at the same time there is the fact that Zenos was a Resonant. And since Resonant are basically people given an artificial Echo, and we know that the Echo allows one to transcend the bounds of existence (or however the line goes), I'm wondering if Zenos can even die. The Sahagin priest who summoned Leviathan way back in...2.2, was it? When Merlwyb killed him, his soul simply possessed a nearby Sahagin and he returned to his normal form. It wasn't until Leviathan absorbed him that he died, similar to how Lahabrea was killed by Thordan. Just something that crossed my mind, though as I said, I'm certainly leaning more on this being a trick of Elidibus' than anything else.