Red Eagle was born in the Sundered Hills, deep within The Reach, around 1E 1030 . As a boy, the village priests foresaw his destiny. He was to become a great warrior and leader who would unite and lead the ten warring kings who ruled the Reach at the time. As the years passed, Red Eagle grew in power and influence and became a prosperous and well known leader.
Around 1E 1055, Hestra, Empress of Cyrodiil attempted an invasion of The Reach. The old kings resisted, but were either killed or bribed to fall under the banner of the Alessian Empire. Eventually, Hestra's legions arrived at Sundered Hills and envoys were sent to bargain for their surrender.
Red Eagle refused to yield the freedom of his people, but the elders were afraid, cast him out, and accepted the Imperial yoke.
Despite his expulsion from Sundered Hills, Red Eagle still held great influence among his people. He gathered Reachmen loyal to himself and his belief that the Reach should be free from Imperial oppression. Together they formed a resistance and successfully carried out raids on the seemingly endless number of Imperial patrols and garrisons throughout The Reach.
One night Red Eagle was approached by a cloaked stranger who revealed herself to be a Hagraven. She offered him power, for a price. Red Eagle agreed to the pact and sacrificed his heart, his will and his humanity to become a Briarheart. From that day forth, his was a spirit of vengeance, pitiless and beyond remorse.
The resistance grew in strength and numbers, and within two years Red Eagle managed to drive the Imperial Legions from The Reach. 
Despite Red Eagle's initial victory, Empress Hestra returned to The Reach with an army unlike any before. For two weeks Hestra's generals laid siege to Red Eagle's stronghold until he emerged, alone and robed in nothing but his flaming sword. It was said that he fought well into the night and slaughtered a thousand Imperials before he was slain. His kin buried his body in Rebel's Cairn, a hidden tomb deep within the rock.
According to legend, he presented his legendary sword to his people, and swore an oath: Fight on, and when at last The Reach was free, his blade should be returned to his tomb so that he might rise and lead them again .
In the Fourth Era, the descendants of the Reachmen, the Forsworn, draw several parallels to the struggles of Red Eagle and his oppression under an occupying force. As such, many of them extol the teaching and practices of Red Eagle and look up to him as a paragon.
Approaching the coffin at the back of the room will cause Red Eagle to rise up along with four skeletal archers at different points around the room. He will typically appear as a leveled Draugr boss, but may appear as a common Dragon Priest at higher levels.
Red Eagle wields a unique Nordic sword called Red Eagle's fury, but sometimes it can be a Honed Nordic Greatsword of Burning. At higher player levels (approx. 40) Red Eagle can be encountered as a Dragon Priest, however he will not drop a mask. Red Eagle uses the disarm shout and Unrelenting force. If the Player is having trouble defeating him, circling around his coffin and using a Bow to damage him may be useful. Unrelenting Force or Ice form shouts can be used to knock him down, give free rein to the Dragonborn to attack while Red Eagle is down. Another possibility is using a Destruction type Staff such as Staff of fireball. Using it will make the battle a bit easier. Summons or followers can be very useful as well, distracting Red Eagle or his skeletons.
An extremely effective way of defeating him is to back-track up the stairs, to the doorway of the secret door. Then use Unrelenting Force to throw him down the stairs, which will damage him quite a lot due to the height of the fall. Then run back and take back Red Eagle's Bane from the altar which you put Red Eagle's Fury into. This action results in the door shutting in his face. He will be stuck down there, giving the Dragonborn time to recharge dragon shouts. The door can then be opened when needed to shout him back down again. Repeat until he is defeated. You can also use fire magic to seriously harm him, as undead are weak to fire.
- It is unknown why Red Eagle appears as a Draugr or Dragon Priest, can shout, and uses Ancient Nord Weapons, as he was a Reachman Briarheart.
- Red Eagle is considered a Dragon Priest, but much like Vahlok the Jailor, he has no mask and was loved by many.
- Red Eagle is thought to be a reference to the character in the Wheel of Time series by Robert Jordan
- In the console version of Skyrim, it is possible to get stuck with having quest items in your inventory. Namely, the Bane and Fury items. To fix this, remove the Red Eagle's Bane from the sword holder to open the chamber the door. Doing this will cause the Bane to be fixed, and completely able to be dropped. As for the Fury, simply place the Bane in the sword holder. This should allow the Fury to become able to be dropped.
- Once this quest has been completed, it is possible to start it over again by reading the book The Legend of Red Eagle. Some Forsworn NPCs will have the sword in their possession (which implies that there are multiple copies of that sword throughout Skyrim). If you have restarted the quest but do not intend to complete it again, do not take Red Eagle's Fury as it will count as a quest item again (you won't be able to drop it without using console commands - Alternatively you can insert the sword back to its place inside Rebel's Cairn to get rid of it). If you do end up with multiple Red Eagle's Fury swords, you can deposit them in the chest in the main chamber of Rebel's Cairn to get rid of them (ps3 and pc). It is not known if the possibility to restart this quest is intentional or if it is a bug.
- Occasionally you will be unable to search Red Eagle's corpse after killing him. This can be fixed by using the wait command for an hour and trying again.
- Sometimes you will find the sword on a Forsworn NPC and have the "quest started" display on screen but it won't appear in your quest log, making it impossible to get rid of the sword. It can be removed with the following console command: player.removeitem 9fd50 1
- On the PC version of Skyrim when you open the Map you will appear to be at the most North-West corner of the map. Also the map will display incorrectly and be glitched. This allows you to see the map of Skyrim from a completely different 'angle'. (I tried taking a screenshot but for some reason I couldn't. Someone else can by simply going into the place and pressing 'M' to view the map).
- Upon completion of the quest, the game may reassign the quest without rereading The Legend of Red Eagle. Multiple copies of Red Eagle's Fury can be obtained through the glitch, but not Red Eagle's Bane. Red Eagle can't be fought again through this glitch.
- One other way for console gamers to remove Red Eagles Fury from the inventory is to try and place it in a weapons rack. It won't go on the rack but rather fall to the ground nearby.
- Found on the PC-Version 1.9.32, when casting the dragon shout "Unrelented Force" at Red Eagle, he tends to stand still after getting back up. Red Eagle then does not go out of combat and is still vulnerable, but not moving. Casting the same shout at hime again seems to resolve the problem.
- PS3: When transforming into a werewolf, Red Eagle seems to ignore the player thus acting as a passive draugr even when attacked. But still marked hostile on the compass