of course necro , Necro Useful for War . they can give you venom cloud and the cast very fast although newly spawned . and have the curse that can give you -100 al stats . and the AOE skill can explode anyone who try to touch him/her :D
this guide really succesful for me . now , when i use RM . every mages cant kill me because Rune Of Silence . they're dead because poison . btw , my RM from Warlock :)