You can get rid of every single one and killing all of them permanently, you can technically play the game solo but good luck with some of the fights. some of the enemies will one shot you.
Lulz, 681.3 hours playing SOLO, testing out SOLO builds, equipment and weapon(s) load outs, etc.
No 'good luck' needed or required. All you need is an understanding of the class you play, the game mechanics, encounter familiarity, understanding of feats, etc.
Current EA Act 1 is cake, but 'good luck' to some of you who actually attempt to try to SOLO and get off the training-wheels full party mode. ;-)
