This prison dimension was really convenient, at the moment it was not used as a prison but rather as a meeting point. All the Warrior Spirits under his command had access to it and Mykael, Lucas and Colin were rare exceptions who also had access to this dimension, so no matter where they were, they could all meet here.
Caleb was the first to react and he whispered after kneeling next to the demon to check on his condition : "That's impossible, he died 17 years ago, I saw his body..."
But the fact that Connor kept calling Derek even when he was unconscious was an irrefutable proof that this demon was indeed him.
Elias sighed with relief and he asked him : "Just tell me that this Derek is still alive, like that I could give that good news to Miguel."
Caleb nodded and he put Connor over his shoulder before saying to Elias : "Connor was the leader of the demon rebellion against their despot King, who we're pretty sure now is a Titan."