Tuskbeasts

The ogres call them tuskbeasts. Most humans think they're a myth, or some kind of weird practical joke. But, they are real, and enormous, and very strange by the reckoning of any but ogres. Found exclusively in the firelands, Caernalin, they are monstrous, twice the size of any horse, and covered in a thick, armor-like skin. Fortunately, when left to their own devices, they are shy, docile creatures. Patient and enduring, the ogres domesticated them long ago, and have since found all of the sustenance they've needed in their companions.
Of course, there is a problem with using the tuskbeasts for food. Not only does their armor make them nearly impossible to kill via traditional methods, if anything does manage to spill their blood, the whole thing instantly becomes toxic. The only way to eat a tuskbeast was if it died of natural causes. This suited the ogres just fine, as they were rarely in a particular hurry to eat the beasts, and treated the occasion reverently when one did die and give them a feast. What they do provide in excess is milk. Ask any ogre and they'll tell you Caernalin tuskbeast milk is the finest meal in Alkurah. Some propose it is magical, and provides some kind of shock to the ogres. The only problem is that their milk smells like cat urine, and most humans are unable to bring themselves to stomach the stuff to prove one way or the other.
The ogres who heard them are shepherds, and do not often go to war, but when they do there have been reports of ogres riding tuskbeasts to battle. Long as a spear, their serrated horns were known to tear through steel and leather armor alike as though they were paper. An interesting note of history is the Milkcart Massacre, during which Therian surprised a Korzian invading army by hiding among milk carts being pulled by allied ogres. They took the Korzian force utterly by surprised and slaughtered them to a man, buying peace at a hefty cost.