Demeton's trash can be pulled without agroing him. I have not tried to pull him without clearing all the trash.
Demeton has 2 Million health, hits between 1.5 and 7K, rampages, and cannot be slowed. He casts two AoEs that are easily resisted with capped resists.
All loot from this event drops from Demeton. A level appropriate six box group can defeat this encounter in slightly less than an hour.