The updated version of avernus will include a wandering boss called Daedeus, The Unbound and will be an epic level boss. This boss will wander the first area of Avernus.
Avernus will have non hostile devils, and hostile devils. Each are separated into different factions as a means to ensure being attacked by a hostile devil doesn't trigger a response from a merchant devil. Not every devil in the bronze citadel will attack the player, but within Bels fortress they are 100% guaranteed hostile with the exceptions of Bel and Zariel.
Darkspire is the location of the portal back, however a quest is required to unlock the portal first. Each player will have to complete it and acquire the item needed to use it.