How does the Warlock Infernal work?

This same faction hunter kept trying to kill me by pulling mobs and feigning death. Eventually I tried casting inferno on him and breaking the bond, but it came right for me. Will it always come for me first? I ended up just running away until it deagro'd, but when I went back it wasn't there. Will it disappear if I leave the area? If I banish and leave the area, will it attack what's around?I can't seem to find any info on how this thing works.