The orcish race was long ago corrupted by the Burning Legion. Having been sent to Azeroth to annihilate humanity, the orcs forced war upon the human kingdoms, which would later be known as the First and Second Wars. Although the Horde almost succeeded, the orcs collapsed from within. After the defeat, the orcs spent a long time as prisoners and slaves. Many years after, a young orc warchief rose to power to lead his people out of their captivity. Under this new rule, the orcs freed themselves from humans and the corruptions of the demonic Legion, once again following their shamanistic ways.
Thrall, the young leader, led his people to Kalimdor, where he faced the Burning Legion again. But with the aid of the Humans and Night elves, they were able to defeat the Legion and find a home in the wastelands of Durotar, founding Orgrimmar as their capital.
The Mag'har Orcs are from an alternate timeline, where it's been a few decades since the events of Warlords. In this alternate timeline, the Army of Light is overwhelmed with power, as they hunt any Mag'har Orcs who don't convert to the Light. Yrel, the leader in this alternate timeline, works alongside a maniacal and Light twisted Garrosh Hellscream. Alive and well in this timeline, Garrosh is referred to as Exarch Hellscream.
In the end Grommash, a valorous chieftain, sacrifices himself so that some of the Mag'har Orcs can escape, leaving Overlord Geya'rah to lead her people to Durotar.
Female: 6' - 6'5 Male: 6'5 - 7'0