We checked the Lepharist Secret Laboratory and the Lepharist Research Center, but failed to find any Odium.

Instead, we discovered that they were running experiments on living creatures.

Player: "Oh. Well, that's... bad."

Quite.

This wasn't the mystery we were intending to solve, but at least now we know what happened to the missing priests.

The Odium, however, is still missing.

Player: "And I'm still looking."

I put my faith in you, Daeva.

I would suggest checking Arbolu's Haven and Jeiaparan Village for clues.