Malacath

Malacath (Daedric: ) is seen almost as a heretic among the other Daedric Princes. His fabled weapon, Scourge, is cursed and will cast any Daedra that touches it to Oblivion. He seems to enjoy watching mortals fight amongst themselves. Malacath's sphere is the patronage of the spurned and ostracized, the sworn oath, and the bloody curse. The summoning date of Malacath is 8th of Frost Fall. Malacath can also be summoned in his shrine, if the summoner offered Troll Fat. While not technically a "good" Daedric Prince, Malacath does have to a certain degree a sense of honor. In the Skyrim quest "The Cursed Tribe ", he tells the Dragonborn the reason he cursed Yamarz was that he always tried to plot and scheme his way out of his responsibility as chief.

Plane of Oblivion
As recorded in "The Doors of Oblivion", Malacath maintains a plane of Oblivion called Ashpit; an ash-grayed realm without sky or ground, only particles of ashes that are floating, falling and whirling. It is where anguish, betrayal, and broken promises swirl like ash in the bitter wind. In, he is also called the Daedric Prince of Orcs.

Merethic Era
During the exodus of the Chimer in the Merethic Era, one of the most powerful Aldmeri heroes, Trinimac, tried to stop the movement. The Daedric Prince Boethiah, the mastermind behind the movement, confronted Trinimac. It was a legendary battle. It is said that Trinimac was eaten by Boethiah, then Boethiah spoke with Trinimac's voice, in order to increase the morale of the Chimer while at the same time mocking the opposed Aldmer. The remains of Trinimac were transformed to Daedric Prince Malacath, and Trinimac's followers were changed as well. They are now known as the Orcs, and they worship Malacath as their god. This is recorded in the "Changed Ones".

Dawn Era
"Orcs were born during the latter days of the Dawn Era. History has mislabeled them beastfolk, related to the Goblin races, but the Orcs are actually the children of Trinimac, strongest of the Altmeri ancestor spirits. When Trinimac was eaten by the Daedric Prince Boethiah, and transformed in that foul god's insides, the Orcs were transformed as well. The ancient name for the Orcs is 'Orsimer,' which means 'The Pariah Folk.' They now follow Malacath, the remains of Trinimac.

Third Era
During the time of the Nerevarine, Malacath was summoned by the Nerevarine in his Shrine of Assurdirapal. The Prince of Curses asked the Nerevarine to track and kill the last of the Oreyn Bearclaw family line. He was upset that Oreyn Bearclaw took all the glory to be a hero while in fact all the deeds were done by Kharag gro-Khar, Oreyn's Orcish companion. The target person was finally killed by the Nerevarine and Malacath rewarded the Helm of Oreyn Bearclaw. However Malacath was wrong believing that the Oreyn Bearclaw's family line has ended, while in fact one of the family members is still alive. This person, named Modryn Oreyn, became a rather important person in the Fighters Guild after his role in the quest to eliminate the dangerous competitor of the guild, the Blackwood Company.

The Hero of Daggerfall received this hammer, decades before, after he did a service for Malacath, which had asked the Hero of Daggerfall to slay a troublesome Daedra Seducer. After wandering throughout Tamriel, the hammer returned to Morrowind and came to be in the possession of Yagrum Bagarn, the last living Dwemer, who had the hammer in his closet. At that time all the enchantment of the hammer vanished, with no apparent reason. It was just a mundane hammer. However, in 3E 433 the hammer came into the possession of Malacath again, and all its powerful enchantment returned. As written above, it was eventually rewarded to the Champion of Cyrodiil. Volendrung is best known for the paralyzing and strength leeching effects it has when hit an enemy.

There is a less well-known artifact of Malacath, named Scourge. The "Requisite Book of Daedra" (under the heading of Malacath) says:

"...yet though Malacath blessed Scourge to be potent against his Daedra kin, he thought not that it should fall into daedric hands, then to serve as a tool for private war among Caitiff and Forsaken. Thus did Malacath curse the device such that should any dark kin seek to invoke its powers, that a voidhole should open and swallow that daedra, and purge him into Oblivion's voidstreams, from thence to pathfind back to the Real and Unreal Worlds in the full order of time."

and "Legendary Scourge" states:

"'The mace Scourge, Blessed of Malacath, Macckan's legendary weapon, forged from sacred Ebony in the Fountains of Fickleire, has ever been the bane of the dark kin, and many a black spirit has been hurled back into Oblivion with a single blow of this bold defender of the friendless.'"

This mace was found in the Battlespire by the unnamed hero of the Battlespire. It changed owners, and finally the mace came to the possession of the Telvanni lord, Divayth Fyr. As any Fyr's artifacts, it was free for the thieves to steal - if they could. It might have passed into the hands of the Nerevarine.

Identity
He is more commonly known as the Daedric Prince Malacath, 'whose sphere is the patronage of the spurned and ostracized, the sworn oath, and the bloody curse.' He is not technically a Daedra Lord, nor do the other Daedra recognize him as such, but this is fitting for his sphere. Of old he was Trinimac, the champion of the High Elven pantheon, in some places more popular than Auri-El, who protected them against enemies without and within. When Trinimac and his followers attempted to halt the Velothi Dissident movement, Boethiah ate him. Trinimac's body and spirit were corrupted, and he emerged as Malacath. His followers were likewise changed for the worse. Despised by everyone, especially the inviolate Auri-El, they quickly fled to the northern wastes, near Saarthal... In Skyrim, Malacath is called Orkey, or Old Knocker, and his battles with Ysmir are legendary." - Original text from the book "The True Nature of Orcs"

Other mentions
Malacath is also one of the Dunmer Four Corners of the House of Troubles. Four Corners of the House of Troubles consists of Molag Bal, Mehrunes Dagon, Malacath and Sheogorath. These Daedric Princes rebelled against the counsel and admonition of the Tribunal, causing great kin strife and confusion among the clans and Great Houses. They are holy in that they serve the role of obstacles during the Testing. Through time they have sometimes become associated with local enemies, like the Nords, Akaviri, or Mountain Orcs. As written in the "House of Troubles" and "Varieties of Faith in the Empire", Malacath is the reanimated dung that was Trinimac, Malacath is a weak but vengeful god. The Dunmer call him Malak, the god-king of the Orcs. He tests the Dunmer for physical weakness.

An interesting record in the "Varieties of Faith in the Empire" says:

"Mauloch (Malacath): An Orcish god, Mauloch troubled the heirs of King Harald for a long time. Fled east after his defeat at the Battle of Dragon Wall, ca. 1E660. His rage was said to fill the sky with his sulphurous hatred, later called the "Year of Winter in Summer".

We know the year is the time when the Red Mountain erupted that brought disasters throughout Tamriel, so it's possible that the claim says that his rage fill the sky with sulphurous hatred is rather exaggerated.

According to Sheogorath, the Backbone of Malacath's realm, Ashpit, is an actual backbone. Although this may just be the ramblings of a madman. Also according to Sheogorath, Malacath is not popular at parties, but more so than Jyggalag, the Daedric Prince of Order, which may refer to how the other Daedric Princes do not recognize him as a Daedric Prince.

Quest
Malacath's patronage of Orcs can be seen from his quest in Morrowind. Here, he has you take revenge for an Orc, who committed suicide after being denied his rightful rewards for a heroic deed. You are sent out to murder the last known descendant of the Dunmer who knowingly took credit for the Orc's deed (another descendant of this Dunmer can be found in Cyrodiil, unfortunately).

Malacath's quest in Cyrodiil involves your rescue of another group of outcasts, namely, a group of enslaved Ogres. He requires an offering of Troll Fat, and you must be level 10 to start the quest. He will send you to the Home of Lord Drad, the slave owner, with instructions to free the Ogres without harming them. After speaking with Lord Drad and then his wife, an easy way to complete this quest is to simply walk into the mine and ignore the guards. As long as you don't attack them they will simply tolerate your presence, and in a simple manner, go to the two Ogre cages and pick the locks of each of the cell doors. Once freed the Ogres and the guards will fight each other leaving you to simply pick what you like from the dead bodies of the fallen. Neither side will attack you as long as you don't attack them, and even if one or more of the guards survives they will not worry as you loot the chests for the various treasures throughout the mine. Note that even if all the Ogres are killed during the battle with the guards, this will not affect the outcome of the quest.

As a reward for finishing the quest, Malacath gives you Volendrung, an enchanted two-handed warhammer.

In Skyrim, an Orc named Atub asks the Dragonborn to bring her Troll Fat and a Daedra Heart so she can pray to Malacath to end the curse he put on the tribe. After doing so, Atub wants Yamarz the chief and the Dragonborn to join in the summoning. He unwillingly accepts and Atub begins the ceremony. Malacath then speaks to Yamarz furious about the Giants overtaking his shrine. He then commands Yamarz to go and bring back a warhammer and then becomes silent. Yamarz becomes angry and orders the Dragonborn to come along with him, stating that the Dragonborn got him into this mess. When they go to the shrine Yamarz wants the Dragonborn to kill the Giant and in exchange, he promises some gold. The Dragonborn can accept the deal, but Yamarz will betray him/her or let Yamarz attempt to kill the Giant only to die in the process. Either way, the Dragonborn must face the Giant. After killing it, Malacath speaks again telling the Dragonborn to take Shagrol's Warhammer back to the stronghold. When he/she returns, Atub asks about Yamarz and learns his fate. Malacath speaks once more telling the tribe that they have earned a second chance. Finally, he tells the Dragonborn to place Shagrol's Warhammer on the shrine and accept the reward. The hammer then transforms into Volendrung.