From its seat, Krugan sighed, for it knew the fight was over. The Khül has already descended from the sky, gracing the orcs of its presence.
Who was Khül? According to their legends, it was the incarnation of one of their dead ancestors, the strongest orc that has ever lived.
Once in a while, when the two suns overlapped, it would once more walk amongst them for a short period of time, sharing its wisdom and strength with the orc kin.
The Grand Duels had two purposes. Firstly, it commemorated the glorious war between humans and orcs that, apparently, happened long ago. Secondly, it prepared the Khül's arrival. Orcs must show themselves worthy and honorable of the Khül's wisdom by challenging humans to a death battle.
The Khül itself would join in if they failed to kill the humans. By doing so, it would teach the orcs how to fight better, at least that's what they all believed.
"Khül and Khan. The white and black sun. As both overlap, they create a grey light. The orcs call it Mürmen. Translated to the common human tongue, it meant the 'plane between life and death.' Orcs considered the grey sun as a sign that the plane of the living and the plane of the deads temporarily fused, bringing back the strongest orc that has ever lived. Meh, an old acquaintance of mine. Orcs think he is honorable and glorious and blabla. But in truth, that idiot was just eager for a good fight."
Extract from, "Yggdrasil Chronicles, The Woodcutter of Iris," by Roan the Merchant.