Red Eagle's Fury

 is an enchanted Sword that is part of the The Legend Of Red Eagle (Quest). It has two identities. The first is Red Eagle's Fury, and the second is Red Eagle's Bane. The Fury version is a quest item that cannot be removed from the player or the player's inventory. The Bane version is not a quest item, and you can do what you want with it.

Red Eagle's Fury
Red Eagle's Fury is gained in The Legend of Red Eagle (Quest). To start the quest, find and read a copy of The Legend of Red Eagle (Book). The Fury is gained at Red Eagle Redoubt.

The sword is a key for Red Eagle's Tomb, inside Rebel's Cairn.

Red Eagle's Bane
Enter Rebel's Cairn and place Red Eagle's Fury in the slot in the pedestal. A stone wall will rise, leading to a tomb and a fight with undead Red Eagle. He will drop a Honed Ancient Nord Greatsword of Burning. After you defeat Red Eagle you can remove the sword from the slot, and it will now be Red Eagle's Bane.

Red Eagle's Bane is useful for fighting the undead, as it makes them burn and flee.

Bugs

 * After completing The Legend of Red Eagle once if the book is found and read again, it will restart the quest and direct you back to the Red Eagle Redoubt. This bug has been fixed with the Unofficial Skyrim Patch.
 * As of v1.5.24.0.5, the bug still exists. However, if you left the sword in the stone in Rebel's Cairn, you can simply remove and replace the sword and the quest will complete.
 * If Red Eagle's Fury is destroyed for enchantment purposes, the quest can be restarted from the book and the sword will be back on the bandit leader's corpse.
 * It is possible to obtain two Red Eagle's Fury on one Forsworn Briarheart at the top of Sundered Towers, during the "Repairing the Phial" quest.
 * Mounting the Red Eagle's Fury on a weapon plaque in a player-owned home will cause the sword to leave inventory and fall on the ground even though if it's still marked as a quest item.
 * If the sword was duplicated using the above method, and given to Malborn during the quest Diplomatic Immunity, an extra copy of the sword will be placed in inventory when retrieving items from the chest.
 * If Red Eagle is fought and killed in the chamber that holds Red Eagle's Fury in the activate weapon slot, it will not transform into Red Eagle's Bane after Red Eagle is killed.
 * The Briarheart who carries Red Eagle's Fury is the one needed to complete the Repairing the Phial quest, and if he is killed and looted prior to starting said quest, the quest may become incompletable.
 * Sometimes when placed in the lock spot to fight the Red Eagle, Upon entering, killing, and looting the Red Eagle, the blade will have dissapeared and there will be nothing but a cloud of smoke in the slot, making Red Eagles Bane impossible to obtain.