The Blades are a joinable faction in The Elder Scrolls IV: Oblivion. They were a powerful group of elite spies and swordsmen in the service of the Emperor of Tamriel. They were founded in the First Era by Reman Cyrodiil..
Later they became an elite shockforce regiment, used to perfection during the Battle of Sancre Tor. After Cuhlecain's death, Tiber Septim became Emperor and the Blades became his bodyguards, and they served the Emperors of Tamriel until the Fourth Era. The Blades fought in several wars throughout history, most notably the Oblivion Crisis. They had secret branches across Tamriel, gathering intelligence on the Emperor's enemies. Fiercely loyal to the Emperor himself, the Elder Council held no power over them. The Blades also served in a public light as the Emperor's bodyguards.
Battle of Sancre TorEdit
In 2E 852, allied Nord and Breton forces crossed the borders into Cyrodiil and occupied the major passes and settlements in the Jerall Mountains. Making their headquarters for the winter at Sancre Tor, the Nord-Breton allies dared Talos, King Cuhlecain's new general, to assault them in their mountain defenses.
When they learned that General Talos had mustered an army in the dead of winter and was marching to assault Sancre Tor, they were elated. Sancre Tor was Impregnable, its citadel on high cliffs overlooking the lower city, nestled in a high mountain basin with steep, Unscalable cliffs in their rear.
The Cyrodilic army was small, poorly trained and outfitted, short on rations, and unprepared for winter campaigning. As their ragged units assembled in the lowlands beneath the citadel, the Nord-Breton allies confidently assumed that their enemy had delivered himself into their trap.
The citadel was not only protected by an unscalable cliff in front and unscalable heights in their rear, but the entrance to the citadel was magically concealed under the appearance of a large mountain lake in the basin beneath the heights. Accordingly, the Nord-Breton allies left on a small force to defend the citadel, descending through lower passages to attack and overwhelm the cold, hungry Cyrodiilic forces before them. They expected to defeat, overrun, and annihilate General Talos' army, leaving no one to oppose their springtime descent into the Cyrodiilic Heartlands.
Leaving a weak force in the lowlands to draw out the defenders, General Talos approached the citadel of Sancre Tor from the rear, descending the supposedly unscalable heights behind the citadel, and sneaking into the magically concealed entrance to the inner citadel. This remarkable feat is attributed to a Breton turncoat sorcerer, who revealed both the existence of an obscure mountain trail down the heights behind the citadel and the secret of the citadel entrance concealed beneath its illusory lake surface.
While the Cyrodiilic army in the lowlands fought a desperate defense against the Nord-Breton sortie, General Talos and the Blades entered the citadel, swept aside the sparse defense, captured the Nord-Breton nobles and generals, and compelled them to surrender the citadel and their armies. The confused and demoralized Nord captives, deserted the alliance and swore loyalty to Tiber Septim. The High Rock generals were executed and the captive Bretons imprisoned or sold into slavery.
During the Oblivion Crisis, the Blades played an important role in the defeat of Mehrunes Dagon, the Daedric prince of destruction, after the death of the Emperor. The prisoner who would become the Hero of Kvatch after receiving the Amulet of Kings from Emperor Uriel Septim VII took it to Jauffre, the Grandmaster of the Blades, and was subsequently sent to find and rescue the last heir to the throne, Martin Septim, and later the Amulet of Kings after the Mythic Dawn stole it from Weynon Priory. The Blades participated in the Second Battle of Bruma and the Battle of the Imperial City. After the sacrifice of Martin Septim and the end of the Oblivion Crisis the Blades were once again without an Emperor to protect and eventually aided the Elder Council to stabilize the Empire.
The Blades have acquired several artifacts over their long history. Many of them are still unknown, but many more are kept in their secretive and impenetrable fortress, Cloud Ruler Temple, in the Jerall Mountains north of Bruma.
- Armor of Tiber Septim: The Armor of Tiber Septim himself. After his victory at Sancre Tor, Tiber Septim made a present of his bloody gear to the Blades. The Blades built a shrine around the cuirass deep in the catacombs of Sancre Tor. And in the years that followed, the location became a pilgrimage site for the Blades. Then the Underking settled in Sancre Tor. It claimed the four mightiest Blades of Tiber Septim's time, Alain, Vlademar, Rielus, and Casnar, and it had been centuries since a visitor had returned from the shrine until the Oblivion Crisis.
- Dagger of Sparks: A weapon from a Blade that perished at the Battle of Sancre Tor, and was later stored in the catacombs.
- Amulet of the Ansei: An enchanted amulet that belonged to the famous Blade, Rielus. It was a gift to him from Tiber Septim.
- Mishaxhi's Cleaver: An enchanted Akaviri Dai-Katana that disintegrates armor. It was a gift to Casnar from Tiber Septim. It once belonged to the Great Akaviri Commander Mishaxhi.
- Valdemar's Shield: An enchanted Blades shield that was a gift to Valdemar from Tiber Septim.
- Northwind: An enchanted Akaviri Katana with a frost enchantment. It was a gift from Tiber Septim to Alain.
- During the Weynon Priory Quest, if asked about Cloud Ruler Temple, he will reply that Cloud Ruler Temple was "built back long ago, by the founders of the Blades, back in the days of Reman Cyrodiil, suggesting the order was founded during late First Era. This is confirmed in The Elder Scrolls V: Skyrim 
- It is worthy of note that their armor and weapons are of Akaviri influence, such as the lamellar armor and katanas, which are similar to the armaments used by the Japanese samurai.