Tinfoil hat time, Oribos would probably works as a part of the final raid(or at least dungeon)/be expanded for the final raid. The current two floors we have access to could easily be turned into a boss areas.
The third boss of the raid would be Arbiter herself. The platform where we met her seems big enough to support a raid. And considering she is the final key, The Jailor could easily turn her against us and maybe use Oribos to get the first ones.(we have been told Oribos is made from an unknow material, maybe it is made from whatever the first ones homeworld is made of?)