The Blades are a faction founded in the Third Era by Tiber Septim. They were designed to function not only as the Emperor's bodyguards, but also as agents throughout the Empire, serving as spies and doing the Emperor's bidding.
The Blades are said to have originated in Akavir, where they were known as the Dragonguard. Originally part of an invasion fleet, they became bodyguards to Reman Cyrodiil after being defeated by him in the battle at Pale Pass. After the battle, the surviving Akaviri proclaimed Reman to be the Dragonborn they had been searching for. Traces of the order's Akaviri ancestry appear in their sculpture, weaponry, armor, and architecture.
The Blades can trace their lineage back to Akavir in the First Era, where the fiercest warriors of the land were known as the Dragonguard. These warriors were charged with not only protecting the rulers of their kingdom, but were also responsible for hunting and killing the native Dragons that plagued Akavir in ancient times. The Dragonguard hunted and killed many Dragons, and followed those that fled to Tamriel in the late First Era.
The Dragonguard invasion of Tamriel was fueled not only for their oath to exterminate the remaining Dragons, but to search for the fabled Dragonborn.  They arrived at the northern most point of Tamriel - Skyrim, and marched south defeating scores of both Dragons and Nords alike until they were stopped by Reman Cyrodiil at Pale Pass.
Reman was the first person who united the human lands of Cyrodiil and in doing so defeated the Akaviri invaders. The remaining Dragonguard, upon hearing the voice of Reman, knelt and swore their lives to him. They had found the Dragonborn they were searching for. 
The Akaviri were the first to proclaim Reman Cyrodiil as Dragonborn. They were also the ones who did the most to promote his standing as Emperor, although Reman himself never took that title in his lifetime. The Reman Dynasty ruled over Cyrodiil in the late First Era, and the Dragonguard became the personal guard of Reman.
Around this time Emperor Reman II permitted the construction of Alduin's Wall in 1E 2812. It's purpose was to record the accumulated dragonlore and prophecy that the Dragonguard possessed at the time, primarily as hedge against the forgetfulness of centuries.
As the years passed, the order grew to become the Blades. As the extermination of Dragons was complete, they only sought to protect the Dragonborn, and through him, the Empire.
Height of PowerEdit
This continued well into the Third Era where they reached the height of their power. By this time they had grown into a much larger organization, stretching to every corner of Tamriel. Agents were of every race. They were merchants, thieves, craftsman, mages, and warriors, all acting as spies, protecting the Empire as needed, and operating in secret.
They often acted alone, but they also met in secret fortresses across the land. The most well known being Cyrodiil's Cloud Ruler Temple, where it was said they hung the swords of those slain protecting the Emperor.
Other maps speak of Wind Scour Temple located under the great expanse of Hammerfell's Alik'r Desert, Sky Haven Temple located high in the mountains of western Skyrim, and Storm Talon Temple located east of Wayrest in High Rock.
With the death of the last Dragonborn emperors, Uriel Septim VII and Martin, the Blades abandoned their role as bodyguards to the new Emperor on account of him not being Dragonborn. The Third Era came to a close with the Blades fortifying themselves deep within Cyrodiil's Cloud Ruler Temple, as they waited for a Dragonborn to return when they would be called upon again .
DownfallEditDuring the Fourth Era, the Blades were effectively wiped out by the Thalmor.
On the 30th of Frostfall, 4E 171, the Aldmeri Dominion sent an ambassador to the Imperial City with a gift in a covered cart and an ultimatum to Emperor Titus Mede II. One of the several demands included disbandment of the Blades. Emperor Titus Mede II rejected the ultimatum. The Thalmor ambassador upended the cart, spilling over a hundred heads on the floor: every Blades agent in Summerset and Valenwood. And so began the Great War.
Eventually, the war ended with the signing of the White-Gold Concordat. Among its terms included the dissolution of the Blades. This allowed the Thalmor to systematically hunt down almost each and every Blade throughout the Empire. Due to this, Esbern and Delphine are the only Blades that are known to remain. And possibly Fultheim, as he is seen carrying a Blades Sword, hinting him as being a veteran.
During the Dragon Crisis in Skyrim, the remnants of the Blades began recruiting again, seeking to rebuild their numbers. With the return of the Dragonborn they regained their original purpose.
The leader of the Blades is referred to as "Grandmaster". Only two grandmasters have ever been documented: Jauffre, who served Martin and Uriel Septim VII during the Oblivion Crisis, and Delphine, a Breton woman who helped the Dragonborn defeat Alduin during the Dragon Crisis of the Fourth Era.
Knight Brothers and Knight SistersEdit
Members of the order are called "Knight Brothers" or "Knight Sisters". The Hero of Kvatch, notably, held this rank among the Blades. Members are given a commemorative set of armor and a katana. When a Blade falls in battle, honorably, his or her sword may be placed on display as a sign of honor, as evidenced by the display of Captain Renault's katana at Cloud Ruler Temple.
For information about the Blades in specific Elder Scrolls games, please see the following:
- The Elder Scrolls II: Daggerfall (First appearance)
- The Elder Scrolls III: Morrowind
- The Elder Scrolls IV: Oblivion
- The Elder Scrolls V: Skyrim
- ↑ The Elder Scrolls IV: Oblivion
- ↑ Events in The Elder Scrolls III: Morrowind
- ↑ 3.0 3.1 3.2 The Book of the Dragonborn
- ↑ Pocket Guide to the Empire, First Edition: Cyrodiil
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 The Rise and Fall of the Blades
- ↑ Remanada
- ↑ The Infernal City
- ↑ The Elder Scrolls V: Skyrim
- ↑ The Great War
- ↑ Dialogue with Esbern (Skyrim)