They do this not just out of necessity but for glory and the chance to be recognised by the Chaos Gods. No crops grow here so they must raid south to survive.

They are savage and brutal, for the lands are harsh, full of ice-covered fjords and roving monsters. To the north of the Old World lies Norsca and beyond that the Chaos Wastes, which lie in the shadow of the Chaos realm - its people the Gods primary pawns. For most in the Old World who are aware of such things they are Khorne the Blood God, lord of murder, rage, violence and battles Tzeentch the Arch-Manipulator, master of magic and weaver of time Nurgle the Lord of Decay, father of plagues, poxes and contagions Slaanesh the Dark Prince of Chaos, the great summoner of excess, desire and perversion. The Chaos Gods have many names and aspects. It is these omnipotent beings that control the fates of all, viewing the world as a game board, the mortal denizens on it as nothing more than playing pieces to be pushed aside and destroyed at will. Over time, this force coalesced into the Chaos Gods the Ruinous Powers. Unknown to them, the empyrean was home to the sub-conscious desires, aspirations and emotions of all sentient races. This is the legacy of the Old Ones, an ancient star-faring race who, in their arrogance, used the immaterial dimension to travel and manipulate the tangible. Chaos - and all magic, for that is of Chaos - seeps into the world from the two poles, one of which lies at the Realm of Chaos in the far north. To explain Chaos is to define the undefinable it permeates the world - the ultimate foe against which the forces of Order must battle to survive. Are they even Human? All the evidence is that they are not rather, these creatures are spontaneously generated deep within the Pits of Chaos in the Icy Wastes north of Norsca, born from the cosmic flux of creation that is primal Chaos.' 'Is there one single greater threat to civilisation than these savages? Physically powerful, armed and armoured with both steel and sorcery, filled with evil intent.

Total war warhammer warrior priest