The Cursed Tribe

Background
"The orcs of Largashbur are beseiged by giants, and have been forbidden to leave their stronghold. Atub, the wise woman of the tribe, has asked me to find her Troll Fat and a Daedra Heart so that she may contact Malacath for guidance."

Quest
When you arrive at Largashbur there are some Orcs fighting a Giant, you need to kill the giant or simply watch the Orcs kill the Giant. Atub will start a conversation when you get near her, and the quest begins.
 * Bring a Daedra Heart and a Troll Fat to Atub.
 * Observe Atub's ritual.
 * Speak to Chief Yamarz.
 * Meet Yamarz at Fallowstone Cave.
 * Protect Yamarz.
 * Defeat the Giant.
 * Take Shagrol's Warhammer back to Largashbur.
 * Place Shagrol's Warhammer in the Shrine in Largashbur.

Walkthrough
Largashbur is an Orcish stronghold found near the Jerall Mountains in the south of Rift. As you approach the stronghold, the tribe of orcs will be engaged in battle with a giant. If Ugor, one of the orcs fighting the giant, dies entering the stronghold and starting the quest will be more difficult. If it is not possible to save Ugor, the stronghold may still be accessed by climbing the mountainside bordering the far left side of the entrance. Upon talking to Atub, the gate will unlock. Another alternative is to steal any of the equipment from Ugor laying on the ground. This will cause the Orcs to accuse you of stealing and they will unlock the door and come out of the stronghold. At this point the player can pay to gold as a fine and be able to enter. Additionally the Orcs will unlock the doors and come out to fight any wild animals, such as bears, that attack you near the gates. Finally, if the player has completed The Forgemaster's Fingers, the gates are unlocked.

The Orcs will initially be mistrustful of you. The one exception is Atub, speak with her to find out that her tribe has fallen on hard times. Chief Yamarz, the tribe's Chief, has become weak and cursed. The giants have taken advantage of this, assailing the stronghold regularly. Atub asks you to bring her Troll Fat and a Daedra Heart as an offering to Malacath, the patron Daedra of the Orsimer, in hopes that he might respond to the wise woman's prayers and guide the tribe in their time of need.

The Ritual
Once you have given Atub the ingredients, she will insist that you observe the ritual of contacting Malacath. She will speak to Yamarz, who begrudgingly allows the ritual to occur.

Malacath is displeased with Yamarz, who has allowed giants to overrun the Daedric Prince's shrine. The god demands that Yamarz bring him the giant leader's club as an offering; only then will he consider lifting the curse.

Upon speaking with Yamarz, he will blame you for bringing this task upon him and tell you to join him at Fallowstone Cave, the entrance toward Malacath's shrine.

Fallowstone Cave
Meet up with Yamarz at Fallowstone Cave, located northeast of Riften. Be prepared to fight several giants, and possibly cave bears and trolls as well. You must protect Chief Yamarz as you travel through the cave until you reach the Giant's Grove on the other side. He is well equipped with full Orcish Armor and an Orcish weapon, and can handle himself well in battle. Still, he will find himself outmatched fighting giants by himself. Yamarz prefers melee attacks, so it may be best to hang back and pelt your gigantic enemies with arrows or magic while Yamarz fights up close. Be careful not to attack the orc Chief; it is easy to accidentally hit Yamarz as the two of you take on the giants.

Giant's Grove
Once you have reached the Giant's Grove, Yamarz will ask you to retrieve the giant chieftain's hammer for him. He promises gold in return for your discretion; the tribe never has to know that their chief wasn't the one to return the giant's club Shagrol's Warhammer. However, upon defeating the giant, Chief Yamarz attacks you to ensure that you will not talk. Alternatively, the player can convince him to attack the giant himself. This ultimately gets him killed and it is up to the player to defeat the giant.

Malacath's Reward
Return to Largashbur after you have defeated Chief Yamarz. Atub asks for news of Yamarz, and Malacath will speak to the remaining tribesmen, telling them of Yamarz's treachery and weakness. Malacath gives the tribe a chance to prove themselves, appointing Gularzob the new Chief.

The daedric prince then rewards you for your worthiness, instructing you to put Shagrol's Hammer on his shrine. The hammer is transformed into Volendrung, the Daedric Prince's legendary warhammer.

Ogol and Lob will be available as a followers upon completion of this quest.

Bugs

 * After putting Shagrol's Hammer on the shrine, it should be transformed into Volendrung, which will appear on the antlers of the deer skull on the shrine. However, there is a possibility that Volendrung will either drop off the antlers or not spawn at all. Make sure that you are looking AT the antlers when you activate the shrine, not looking downward, since Volendrung seems to spawn where you are looking.
 * If looking around the shrine yields nothing, loading a previous save should cause Volendrung to spawn properly. Alternatively, just hit the altar and the stone a few times until the weapon pops out.
 * Sometimes people will respond as if you have already gone through the ritual when you reach the appropriate level for the quest. Even though his people act as if he is dead Yamarz is still alive. It is believed this happens if you enter the compound before the quest becomes available. If this happens the only fix is to load a save previous to entering the compound. If you do not load Volendrung is unattainable. This bug if not the cause is confirmed.
 * Initialing a dialog with sleeping NPCs in Largashbur Longhouse will not cause them to get up and speak to you as per normal; they will continue to sleep while talking.
 * After you start the mission, Yamarz will start his trek to the cave, you may follow him. As he makes his way to the cave, he might take a swim through the lake near Riften. If he does, and you follow, the PS3 will log you out of the game as if you quit from the center PS button.
 * At least for one game that I've found so far, Atub is nowhere to be found in the longhouse or any where in the area, this occurred when Ugor is dead.
 * NPCs appear to be stuck in the Longhouse and will not leave, move, or walk. Atub is missing and Ugor is dead. Two unidentified Orc bodies are found near or in the compound.
 * When first approached on your return, Atub is very hostile and demands what you, an outsider, are doing there, as if she had never seen you before. Talking to her jogs her memory.
 * If you approach the altar too closely and accidentally knock into the objects on it, Atub may become hostile and demand recompense in blood or money (250 gold).
 * If you enable all map markers via console and have not started this quest do not fast travel to Giant's Grove, you will not be able to fast travel out and will have to no clip through a blocked wall to gain entrance to Fallowstone Cave in order to get back to Skyrim. and if you kill the giant and take Shagrol's Hammer before starting the quest, the quest will start. If you start the quest this way it will break the quest and make it impossible to complete without using console.
 * If you follow Yamarz, he will take the path through Riften. The game may freeze if you go to the lake and swim around instead of entering Riften.
 * If you enter immediately after Yamarz he will not be in there, instead he will be outside not moving, only giving short responses.
 * Sometimes inside the cave the bears get stuck in the ground, being unable to be killed by you or Yamarz. This stops any progression towards the grove. Can be fixed by reload or using the Animal Allegiance shout or the Unrelenting Force (level 3) shout to get the animal unstuck. Then kill the animal and move on.
 * After the battle between the Orcs and the giant ensues, upon first approaching Largashbur, Atub may not open the front gate and stand silently above the stronghold's wall. There is no way to speak to her from outside. A known way to resolve this glitch is to follow the fence toward the cliff wall on the right side. There is a spot where you can repeatedly jump until you're over the wall. The orcs will not be hostile, and you can now approach and speak to Atub. This bug may occur if Ugor is killed by the giant, and hence Ugor and Atub's conversation prior to opening the front gates cannot commence. Another fix is to hit Atub with an attack and when she comes down pay the bounty and you can enter freely.
 * When you kill the giant at Giant's Grove, it is sometimes only possible to loot it for the few seconds before Malacath begins to speak.This makes it impossible to complete, because you cannot obtain the giants hammer. It is possible that this occures because you let the giant kill Yamarz, before you kill it.


 * If Ugor and the other Orcs are fighting the giant and you leave you come back to find all of the Orc guards and Ugor dead.

PS3: Sometimes no one is outsode to start the quest. There is an opening in the gate near the goats, shoot an arrow at a passing goat and Atub will come out. (PC, 360 unconfirmed)