The ??? spawns in the corner of a room at either (H-8) or (G-8) (room closest to the H-8 path) (There may be sparkles???) Try not to fall down the holes in the floor. Click on it to obtain a Bucket of Divine Paint.
Return to Virnage to receive a Letter from Virnage.
Virnage needs a bucket of divine paint to restore the statue of Altana to Her former glory. He advised you to look for it in a citadel on the Sauromugue Champaign.