The Eidolon Sword

Full Item Description
The Eidolon Sword is a very unique relic, as when viewed through an object of true sight or something that can penetrate the arcane realm of illusion or realms of fae enchantment the sword has neither form nor shape, color, or texture. It is a matrix of magical energy, a thing of pure essence and will, and that will happens to express itself as a sword, though the sword that manifests from user to user is different.

History
The Eidolon Sword was a treasure of the Raksha Lord Whose Eyes Weep Flame, a ruler of a particularly harsh faerie realm of boiling sands, illusionary water and rather brutal nightmares of undeath. This was so as he and his chimerical land were born from the hallucinations of desert travelers, and their despair as they fell one by one to the heat and poison of the desert creatures. Looking much like a lion-head jinn of savage disposition, the Lord Whose Eyes Weep Flame lorded over all those who made their residence in his realm.

Eventually it came to pass that a group of heroes of the old world came to the realm of the Sands that Boil and made war upon the Lord Whose Eyes Weep Flame. Though mighty, the Lord's powers were chaotic, and their effects often ephemeral. Contrary to this, the newcomers were focused, and their powers resonated with the tang of calcified form. Though many of them were slain, so too was the raksha lord. It was with his own chimerical sword that the Raksha was slain, as the greatest warrior of the newcomers stole the weapon from it's sheath and turned the golden scimitar of flame against it's master.

The newcomers abandoned the land of Sand that Boils to return to their homes, but as they passed from the realm of the fae to the realm of man, the warrior and the Eidolon sword were seperated and the sword was hurled through the aether until it buried itself deep into a stone almost to be forgotten.

Later a young man, urgently needing a sword would find it, and draw the magic blade from the stone and begin his own march to greatness.

Magic/Cursed Properties
The Eidolon Sword is the essential magic sword, it's powers undefined and even it's shape malleable. It can only be drawn by a mighty soul, be it a king or a tyrant, a hero or a black hearted villain. The sword appears to be the ideal weapon of the person who draws it, and in reverse, the weapon is also an extension of the person who draws it. Thus the noble-hearted barbarian who draws the blade will find a magnificent two-handed war sword with spartan decoration, but a blade that is mighty enough to cleave stone. Likewise a defender of the forests and brother to the elves will find a slim elven longsword with suitable elvish prose decorating the tang of the blade. A reviled blackguard would find his magic sword to be a thing most vile, a black blade acid etched with eldritch runes, sheathed in ectoplasmic green flame.

The Eidolon Sword is also a weapon of growing enchantment. It is always going to radiate strong magic, but the weapon grows in power with the experience of it's user. In game terms it begins as a magic sword +1 and progresses in level with the character as said character grows themselves (levels up, gains experience). As a sword of pure magic, the blade can be used to deflect magic spells, and the blade cannot be broken by anything less than a greater divine power. It is a legendary artifact, though it is known by dozens of other names and only the most erudite or magical sages would know the truth of the Eidolon Sword, and why the world has not been overrun with weapons of world shaping power.