Shades are weak to slash and icefiends are weak to stab... I discovered the icefiend issue when i was using a promethium maul and could only hit 0's.. and my mate using fire surge couldn't hit at all (it was a level 182 icefiend though) and then our third companion came up using a spear on stab and 3 hit killed it... when the icefiend had almost killed me and my mate (we both lvl 130's+) and personally i found hydra's use mage and ranged it changes based on what prayer your using... there's a red ball, and a blue dart looking thing