He developed depression precisely because he was forced to be trapped in this cage.

BTW As for his good buddies in Hell (the Ring Lords), rather than revering him, it's more like he's the one they all dote on (the group's favorite), right?

To him, Hell is a cage, and sinners are the instruments of his punishment (he must witness firsthand the severe consequences of the sin he committed back then). But his true nature has always been that of a pure-blooded archangel, full of imagination and creation.