I have a cleric of Aramon and when i went into shadow demon room, obviously none attacked me, since they are undead. But when Beren and Midori came in to assist me, all of the shadow demons started attacking me. Is this a bug or are mobs now set to assist each other, no matter what class you are? My Cmud is lame so I cant post any caps... sorry!

If you vig them or they vig you, you are attacked, just like with any other mob.

any mob with an intel 12 or higher will attack any viggers.