From publisher blurb:
A look at B/X D&D from the other side…
In Life of Rage, the players are orcs and goblins, and the humans, dwarves, and elves are the enemy. Explore the culture of the orcs as they struggle to establish their own homeland in a remote region of the world.
Included are four new classes, and rules for covering such things as Shamanistic magic, rage, and glory. Also included is a detailed description of orc society and culture, all set within a world that is detailed enough to provide a good background, but open enough for you to make it your own.
Designed to be compatible with B/X D&D, and the various retro clones, Life of Rage requires the use of one of those core rules sets.