So it seems like the three worst enemies of the Deltas' are Dean Wormer, Greg Marmalard, and Doug Neidermeyer. This is how I would rank them starting with the worst:
1. Doug Neidermeyer
2. Greg Marmalard
3. Dean Wormer
What do you think?
I think we can go to no less an authority than Bluto on the matter. Here was his list in his words "WORMER, HE'S A DEAD MAN. MARMALARD, DEAD. NEEEEEIDERMEYERRRRRRRR...…"
1) Wormer. His disdain and obsession with destroying the Delta's is what drove everything. The other house would not have had any authority to do anything if it wasn't for Wormer's backing. Also, expelling them wasn't even enough for him, he even called their draft boards, which would almost certainly mean Vietnam.
2) Marmalard. Granted he was acting under orders from Wormer, but he was obsessed with using his powers against them as well. Though I give him a pass for the Motel, since he did believe that Otter had slept with his girlfriend.
3) Neidermeyer. I don't think he actually had anything against the Deltas. He was just a sadistic, militant prick, and they were the sworn enemy of his frat.