Orogs are a subrace of orcs living in the underground region known as Underdark.
The orogs originate from a mountain orc faction known as the Skullbiter Tribe who inhabited the Spine of the World many many, many years ago. When the orogs and mountain orcs invaded the human magocracy of Netheril they were cut from the group and cornered by elven and native Netheril people. They fled to a cave which lead to the Underdark. The orogs became lost yet felt safe and not followed by their enemies. They fled further underground. After settling underground they bred in large numbers throughout various caves. They then split into different tribes and found minerals known as metal and ore. The demise of the elven empire led the orogs back to the surface in which they bullied their mountain orc cousins and giving them weapons crafted of Underdark metal.