(Void Knight top,Void Knight robe,Void Knight gloves,Void Mage helm,Void Rnager helm, Void Melee helm) You should have at least any higher combat skill(s):melee, ranged or mage. For mage, you should offer the coins for buying runes.
Full set with Melee helmet gives 10% Attack and Strength.
Full set with Ranger helmet gives 10% Ranged.
Full set with Mage helmet gives 30% more accuracy to magic spells.