From Hell the demon lords have all been destroyed but 5 of Azmodan's demon generals are still alive, those are
1st Wrath, who is the strongest general alive and probably the leader of the demons now
2nd Pride
3rd Greed, also known as ''Lord Greed'' who is the second strongest after Wrath and he has the treasure goblins as his servants (and maybe he is the jeweler guy that follows you)
4th Envy
5th Sloth
From Heaven there are 3 more Archangels alive, Imperius, Itherael, Auriel.
Imperius is clearly our enemy especially now after what happened at the end of Malthael fight he will want to kill the nephalim at all costs, and if we turn against him its obvious that Itherael and Auriel will stand by his side, only Tyrael will be with us but he isnt an archangel anymore
I suspect that the game will have 3 more expansions one 70-80 levels, one 80-90 and one 90-100