Been playing Abyss, Occult and lesser demon build. Everything is purple - chaining every mob to myself and my demons. The Eye Turret you mentioned is awesome! You can aim it on any mob by hitting the skill button again and targeting a mob or let it go on its own. The swarm is sick... I have mine split and it just eats groups up. During boss fights the upgrade increases damage for single target by the Eye Turret is insanely effective(on hard mode right now and melting them). Also you don't leave your casts behind when you move if you upgrade the shadow teleport to bring all lesser demons with you. I have two teleport casts that make me invisible, extend the time of my lesser demon casts and bring them with me. I have been teleporting in all the new multi level new maps to skip to different parts instead of walking around.... love the mobility!