I'm am also turning into a zerker pure at the moment. : if you start out with 1 defence you can do monkey madness and use the defence xp from the quest then you can do dragon slayer and that will get you to 43 defence, then you can do nature spirit and the quests need to do RFD and get your barrows gloves. but DO NOT TRAIN ANY DEFENCE untill you are done with all the quests you need to do for barrows gloves.