The Sword of Aeons is a bloodforged ancient weapon in Fable, Fable: The Lost Chapters, and Fable Anniversary, in which securing the sword against Jack of Blades becomes a major plot line.
The sword is revealed to have an ancient connection to the bloodline of the protagonist. To be activated, the Sword requires the blood of a descendant of the Archon. Before it can be activated, however, the seal on it must be broken. In order to do so, one wishing to gain the Sword must travel to the abbey in Hook Coast with at least one descendant of the Archon (Although if what Maze says while performing the ritual is any indication, it is preferable to have more) and complete some sort of ritual near the front of the temple. Once that happens, the Septimal Key appears, and must then be used to activate the Focus Sites throughout Albion; doing so reveals the sword. To achieve full power, the Sword requires the death of at least one descendant of the Archon per user. The precise reason for this is never stated, although it likely has to do with the fact that William Black was its first human wielder and his soul dwells within the sword.
The sword itself is acquired in the Chamber of Fate, after Jack of Blades is defeated. In order to wield it, the Hero must sacrifice his sister or the Hero can cast it into the vortex opened by Jack's death and destroy the sword.
Powers and Stats
Tier: High 6-A
Name: Sword of Aeons
Powers and Abilities: Grants the wielder Regeneration (Mid-Low), destructive power equal to Avo's Tear, and grants the wielder a perverse form of immortality (Types 1 and 2) (at the expense of his soul, William Black gained immeasurable power and immortality from the blade)
Attack Potency: Multi-Continent level (Granted William Black the power to defeat The Court of Blades at the expense of his soul. Laid waste to Albion's mountains and carved up new valleys during a weeks long fight with the Queen of Blades. The only Weapon considered to be its equal is Avo's Tear)
Material or Element: Forged from foreign elements of The Void
Needed Prerequisite for Use: Give up your soul to the blade in exchange for its power
Notable Attacks/Techniques or Alternate Forms: Nothing notable