When a prominent orc warchief falls in battle, his warriors sacrifice themselves to recover the body (assuming they are forced to retreat or otherwise routed in battle; most orc warriors, upon seeing their warchief fall, redouble their ferocity and eventually take the field, though still at a considerable cost of life).
The body is arrayed on a funeral pyre and his surviving warriors recount his deeds and their own (for their deeds are are extension of his leadership) before the assembled tribe. Warriors of the Blood Hand tribe will cut themselves and place bloody handprints on the body before placing it on the pyre. The One Eye tribe will remove one of the warchief's eyes (if he has not done so already). And so on.
The body is then burned and the ashes and bones gathered together. The bones are crushed to powder and, with the ashes, are mixed into the food for the surviving warriors as well as the promising warriors-to-be in the tribe. This is to pass on the strength and cunning of the warchief. In the next battle, one of the warriors will show himself to be the new warchief through some act of daring, violence, and ferocity.