Battle of Bladespire

The Battle of Bladespire was the final and most important battle of the conflict between the Bladespire ogres and the Frostwolf and Whiteclaw orc clans, roughly 11 years before the opening of the Dark Portal. It led to the liberation of the mok'nathal half-breeds from their brutal Bladespire masters.

Background
For a number of months, tensions increased between the orc clans of Frostfire Ridge and the local Bladespire ogres. In the south, Highmaul never recovered from the battles with the Warsong and Shattered Hand clans, leading the ogres' hold on Nagrand to be shattered forever and ogre influence across Draenor to be waning. The Bladespire leader, Imperator Kelgrok, was greatly troubled by these events and determined to keep his hold on Frostfire Ridge. To make up for the low ogre population, Bladespire sorcerers had conducted cruel experiments to create new creatures for labor, and the most promising results came from the mok'nathal — the result of selective breeding between ogres and orcs. To maintain loyalty from the half-breeds, the ogres threatened to kill entire families if even one of their members rebelled. Kelgrok unshackled many of the half-breeds and ordered them to make war on the orcs as the bulk of the Bladespire army. The Bladespire forces rampaged across Frostfire, seizing large tracts of resource-rich land from the orcs.

Chieftain Garad of the Frostwolf clan called upon the nearby Whiteclaw and Thunderlord clans to unite with the Frostwolves, but the Thunderlords — led by Garad's estranged son Fenris Wolfbrother — rejected the offer, choosing to instead raid Bladespire settlements at night. The Whiteclaw clan did unite with the Frostwolves, for whom they felt an affinity due to the two clans' many shared customs and traditions. Garad was declared leader of the Frostwolf and Whiteclaw army, and named his sons Ga'nar and Durotan as his lieutenants. The chieftain struck at the Bladespire, and though they didn't win any decisive victories, they did capture a number of mok'nathal, including their elder Leoroxx. Garad was surprised to learn that Leoroxx and the other mok'nathal were not willing servants but slaves. Garad and Leoroxx came to an agreement to help each other destroy the Bladespire clan forever.

Battle and aftermath
Leoroxx returned to Bladespire Hold and incited open rebellion among the mok'nathal. They rose up against their oppressors and set fire to the stronghold as Garad and his army smashed into Bladespire's outer defenses. The Battle of Bladespire dragged on for a full bloody day before the orcs and mok'nathal drove the ogres out. In the heart of the burning stronghold, Leoroxx strangled Imperator Kelgrok with the chains he had worn for so much of his life.

The orcs had won, but at great cost. Hundreds of Frostwolves and Whiteclaws had died in the battle, including Ga'nar, who had sacrificed his life while helping many young mok'nathal escape the besieged fortress. Ga'nar's death broke his father's heart, and although Durotan remained to carry on the family line, Garad never recovered from losing his second son.

After the battle, the Frostwolf chieftain offered Leoroxx and his people land in Frostfire to make a new home, but the elder mok'nathal declined, knowing that the orcs would never truly accept half-breeds. Instead, the mok'nathal settled in a remote, resource-scarce corner of Gorgrond where they could live in peace, only taking up arms to defend their meager lands from threats.

Speculation

 * Upon meeting the mok'nathal Rexxar for the first time, the Frostwolf shaman Drek'Thar claimed to have fought alongside the half-breed's elders on Draenor "many years ago". This was very likely during the Battle of Bladespire.
 * As chieftain of the Whiteclaw clan, Zagrel likely participated as well, but he is not mentioned as doing so in Chronicle Volume 2.