Activating the quest
Notice! This mission is available only for non-Orcs!
In order to receive this mission, you need to reach one of the Orc camps throughout Skyrim. The Orcs aren't very fond of strangers, so they try to isolate themselves. Their camps can be found on mountain slopes, by the borders of the land. Their locations have been marked on the map below.
As you enter any of the camps, you will be stopped by a guard. As long as you stay polite, you won't get attacked. Ask how you can get inside and you will receive the mission of finding The Forgemaster's Fingers. The artifact can be found in a randomly chosen location - prepare for a short fight with a group of enemies. The item can be found inside a chest.
After you bring the Fingers to the quest giver, you will be able to enter any of the Orc camps and use the services available inside (trading, training, crafting). From now on the Orcs will consider you a blood brother.
Note that there's no leader in Largashbur, therefore you can't unlock this quest there. You can however receive the Daedric quest The Cursed Tribe.