These are highly stable living entities, when you piss them off you will know it almost immediately, EVERYTHING will start going wrong. ALMOST IMMEDIATELY. they have the power to replicate ANY MAGICK from ANY ENTITIES see why they chose to stay away from humans? Once the power is replicated, it's theirs, they adjust it to their system. It DOES NOT harm the entity they came across, but, it does give the blood elf a serious advantage as they are able to defend against the others magick then.
They have stayed away from other races for this reason, because they are able after adjustment to wipe out entire races but choose not to.