Summary
The Elder Scrollsfranchise by Bethesda has a massive number of different factions and organizations, each one with its own history - both good and bad - and a list of accomplishments to its name. This expansive lore is one of the great strengths of the franchise, allowing players and fans to become immersed in a rich fantasy world.
With so many factions against a backdrop of magic and many thousands of years of history, there’s some seriously interesting lore. Here’s a look at the worst factions that have done the most harm in the world ofThe Elder Scrolls.

Kalgrontiid, a powerful Dragon, had ambitions far above his station. Not content with being a mere underling to Alduin, Kalgrontiid wanted to supplant the Dragon God of Time Akatosh himself. In the Merethic Era, he terrorized theKhajiit of Elsweyruntil his defeat by the hero Khunzar-ri.
Led by Kalgrontiid, the Order of the New Moon sought to bring about a major cosmological change to the Aurbis, the universe of theElder Scrollsfranchise by elevating Kalgrontiid to a truly divine status. Kalgrontiid and the Order laid waste to vast swathes of Elsweyr during the Second Era, featured heavily inElder Scrolls Online,killing countless people and damaging one of the moons.

2The Alessian Order/Maruhkati Selectives
Slaves Turned Oppressors
The Alessian Order got its start during a great slave rebellion against thevicious and oppressive Ayleids, the Heartland High Elves who once ruled Cyrodiil. Led by Alessia, the Order had a righteous and just cause - the liberation of the Nedic peoples and an end to the atrocities of the Ayleids.
Unfortunately for the Order, it lived long enough to become the oppressor itself. A group of the order, the Maruhkati Selectives, even went on to try and magically strip all elven qualities from Akatosh himself - something which could have had catastrophic consequences for all of Tamriel.

One of the five major Houses of Dunmer society, the Telvanni are an entire faction of mad scientist wizards who know the meaning of the word ethics and disregard it as unimportant. The Telvanni are slavers, but more than that they’re a group of sneaky, vicious, back-stabbing wizards always looking to get an advantage over their competitors.
Thousands upon thousands of people - mainly Khajiit and Argonians - in Tamriel have been enslaved by the Telvanni, and their discarded and escaped magical experiments litter Morrowind and the surrounding areas to the consternation of everyone.

4The Sload
Evil Slugs From Beyond The Ocean
The Sload are a race of slug-like people from far beyond Tamriel. Most well known for their necromancy, Sload are skilled users of magic and seem to be completely amoral when compared with the other Aurbic peoples. The Sload have been involved in numerous painful crises for Tamriel, most notably the Thrassian Plague, which wiped out half of Tamriel’s population - ended by the actions ofBaron-Admiral Bendu Oloof the All Flags Navy.
A sub-group of Sload known as the Sea Sload were involved in plans to sink the island of Summerset, home of the Altmer, during the Interregnum of the Second Era, killing many thousands of people and causing major damage to structures and the environment.

5The Ayleids
Slavery, Daedra Worship, And Truly Grotesque Art
The Ayleids were an expansive, highly variable group of elves who lived primarily in the lands which would later be known as Cyrodiil. Most well known for enslaving the Nedes, various groups of Ayleids were getting up to all sorts of nefarious things in Tamriel.
Many Ayleid societies worshipped Daedra such as Molag Bal and Namira, leading to horrific practices such as the “art” of flesh sculpture - living people twisted into painful and disturbing monstrosities. It’s no wonder their slaves rebelled.

One of Tamriel’s most mysterious and enigmatic groups, the Dwemer have a long and storied history reaching back to the Merethic Era. Most well known for their enduring contraptions and expansive underground cities, the Dwemer also mastered an arcane art known as Tonal Architecture.
But the Dwemer had a dark side. When the Falmer, the Snow Elves, came to them seeking aid against the Nords, the Dwemer offered it - at a cost. The Falmer had to agree to be blinded and changed, twisting them into the aggressive creatures encountered deep underneathSkyrimby unwary adventurers.

7The (Third) Aldmeri Dominion
Warmongers Who Played A Crucial Role In The Great War
The Aldmeri Dominion is an organization with a long history in Tamriel, some good and some very bad. In the Fourth Era, the Third Aldmeri Dominion is responsible for the Great War, leading to the fall of the Empire and the deaths of millions of people. Led by the Thalmor, a sect of religious extremists seeking to outlaw Talos worship, the Aldmeri Dominion controls Valenwood and Elsweyr, and manages to fight the Empire to a standstill.
The Dominion has worked hard to sabotage the Empire, resulting in the civil war inThe Elder Scrolls 5: Skyrim, along with the secession of Hammerfell. All signs point to the Dominion wanting further war - as well as some more esoteric goals involving the nature of Tamrielic existence itself.

Cultists of the Daedric Prince Mehrunes Dagon, the Mythic Dawn were responsible for the Oblivion Crisis that ravaged Tamriel during the Third Era, featured inThe Elder Scrolls 4: Oblivion.The Oblivion Crisis caused widespread devastation throughout Tamriel, unleashing Daedra upon an unsuspecting populace thanks to the masses of Oblivion Gates.
The Mythic Dawn and the Oblivion Crisis, on top of causing many deaths and devastation the likes of which Tamriel had never seen, also created the conditions where the Empire began to fall, resulting in the state of Tamriel seen inSkyrim.

Once a member of the mysterious Psijic Order,Mannimarco is a necromancer without equalwhose actions throughout Tamrielic history have caused problem after problem for everyone he meets. Not content with being a simple necromancer, Mannimarco has an entire order of devotees, the Order of the Black Worm.
Mannimarco was responsible for one of the major crises in the Second Era, the Planemeld Crisis led by Molag Bal. Featured inElder Scrolls Online,Elder Scrolls: Daggerfall,andElder Scrolls: Oblivion, Mannimarco and his Order of the Black Worm have quite the catalog of sins to their name.

10The Daedric Princes
A Pantheon That Is The Source Of Many Evils
As a pantheon, theDaedric Princesare quite varied, but what they do share is an unflinching selfishness and desire to work towards their own goals. Various Daedric Princes have been involved in all sorts of dastardly plots in Tamriel, from Molag Bal’s Planemeld in the Second Era to the invasion of Mehrunes Dagon in the Third.
Sheogorath is a source of madness, tormenting poor souls all across Tamriel, while Molag Bal is the father of vampires. Hircine unleashed his werewolves on the peoples of Tamriel, while even the somewhat benevolent Azura cursed the entirety of the Dunmer race for the actions of three individuals.