Oblivion:When the Vow Breaks

Quick Walkthrough
# Speak with Maeva the Buxom about a missing family heirloom.
# She will direct you to her husband, Bjalfi the Contemptible, taking refuge in Fort Strand.
# Head to Fort Strand, and dispatch all the gang members including Bjalfi.
# Return to Maeva with the mace to receive your reward of a leveled amount of gold.

Detailed Walkthrough
Family Heirloom
Just north of Anvil is a small farm called Whitmond Farm. Go there and speak with Maeva the Buxom. She will ask you to retrieve a family heirloom, a magical mace named Rockshatter, which her husband, Bjalfi the Contemptible, smuggled out of their house before leaving her. He was last seen heading for the ruins of Fort Strand to join the marauder gang there.

Fort Strand
As soon as you start the quest, Fort Strand is added to your map. Head to the fort, and inside there are approximately nine gang members, along with Bjalfi himself, taking residence. The toughest fight is against Bjalfi and his two companions. It is possible to take them on one at a time assuming you are careful. If you fail to do so and they rush on you all at once, try to distract some of them by summoning a decoy. One of Bjalfi's bodyguards is a boss-level marauder. At low character levels they are pretty easy to defeat, but as you level up it may prove rather difficult.

Return to Maeva
After you have killed Bjalfi, take Rockshatter from his corpse and return to Maeva to receive a leveled gold reward (20 gold at level 1 plus an additional 25 gold for each level above that, to a maximum of 745 gold at level 30).

Notes
If you are sufficiently acrobatic, you can jump across the bridge trap and wood planks (if they've also fallen) in Fort Strand. Get on the edge of the wall and Bjalfi and his two partners will run after you, falling into the pit. If you're not sneaking, they will eventually stop in a spot where you can shoot whatever you want down on them. They'll then run out and back around, within a few seconds falling down again. You can repeat this until you kill all three.
Bjalfi can be a good source of leveled heavy armor. He always has the strongest boots, cuirass, and greaves for your level, with a 50% chance of having similarly-leveled gauntlets.
Once you've returned Rockshatter to Maeva, the quest will be complete and she will keep the mace. At this point, Rockshatter is no longer a quest item; it becomes just an ordinary enchanted dwarven mace and weighs as such. You can pickpocket her (or even kill her) to take it back, although you have to try this when Maeva is sleeping, eating, or reading as she equips the mace at other times so it is not possible to steal it from her. Stealing from her and/or assaulting and killing her will not net you a bounty, nor will it increase your infamy. Because of this, and the fact that she does not play a part in the game after this quest, Maeva makes a good entry point for the Dark Brotherhood.
If you've come across Rockshatter by chance without talking to Maeva, your journal will be updated and the quest will be added to your Active Quests list. Just complete it the same way as if you had spoken to Maeva.
Bjalfi frequently drops Rockshatter when you kill him. Once he's dead, pick it up and finish clearing the dungeon before you check his body. You should then find another Rockshatter in his inventory. Leave it there, run to Whitmond Farm and deliver your copy of the mace to Maeva. Afterwards, run back to the fort and loot Bjalfi's corpse. The copy of Rockshatter you had left behind when you were abandoning the fort should still be there. Although you will have had this quest completed by then, the mace will still be treated as a quest item and after grabbing it you won't be able to get rid of it unless you use the game console. See below for more details.
Alternately, speak to Maeva while being on horseback and having Rockshatter equipped. A message will appear informing you that the item could not be removed; nevertheless, you will still be able to finish the quest and keep the mace.
Under certain circumstances, Bjalfi may respawn. You can then slay him once more to obtain yet another copy of Rockshatter. While this is not a particularly devastating weapon, it's supposed to be a quest item and has zero weight. You can return it again to Maeva to get the reward again.
 
 To get around this, you can use the following console command:  player.removeitem     . The Form ID depends on the level you had when you found it. Remove all but one of the Rockshatters from your inventory, then give the last one to Maeva. The Form IDs are as follows:    (levels 1-4),    (levels 5-9),    (levels 10-14),    (levels 15-19),    (levels 20-24), and   (level 25+).

Journal Entries