A wizard named Demain, centuries ago, was experimenting with combining spells and potions to create a new weapon that could win any fight, think for itself - even anticipate blows to block them. However, though strong, Demain was not an experienced magic-user, and he found his mind-giving and magic-lending concoctions spiralling out of control: before he could work out how to null them, the sword he was experimenting on had developed a life and even a personality of its own. Demain could not bring himself to destroy the thing, which seemed strangely out-of-character for him (this was, in fact, evidence that the sword could affect the minds of its bearers to further its own survival): it seemed almost alive. And so he allowed it to develop, and this might have been a wonderful accident, akin to penicillin or the wheel, had not the sword accumulated a love of causing pain. That is, after all, what a sword is made for; and the sword learned from its maker, whose experiments were not always limited to inanimate objects or dead creatures.
It soon found that the easiest way to achieve its goal was to cause the darkest, most selfish desires of those around it to manifest themselves as main goals, forcing them into a long-term cycle of bad decisions and worse consequences. Its first victim, quite ironically, was Demain, whose greed for knowledge grew insatiable till he would do anything to accumulate all there was to know and more. But this had an un-looked-for side-effect. Demain lost interest in all other activities: trivialities such as food and sleep came second-place to his ravenous thirst for information. His hair and beard grew tangled and unheeded to the floor, whilst he grew pale for want of sun; bent-backed and weak-eyed from leaning over tiny print by candlelight every night; thin and gaunt as he wasted away from lack of food and exercise. His book collection was fabulously large, and would have been famous had anyone known of it. He swore an oath never to rest until he knew all there was to know.
When a young man called Hart son of Hamat came upon the lonely house of Demain the Wizard, all he found was a dry body - barely more than a skeleton - hunched over huge crackling tomes of ancient lore. Demain had starved to death. But his oath still bound him, and his ghost still haunts that area; it is most commonly seen in the library, trying in vain to take books from the shelves with withered, insubstantial hands.
Hart had come there, one of those at the head of a large following, after he and some others had split off from their already overpopulated home along with his admirers and struck off to found his own independent kingdom. He gave Demain’s body a decent burial, and then went through his house with his trusted co-leaders, wondering at the strange and ancient books in many languages and setting free the survivors of the wizard’s experiments (explaining some of the more fantastical creatures, such as griffins, that inhabit that area). But Hart found the sword, and Hart kept that for himself, telling no-one else of it - not even his friends.
Hart grew ruthless and cunning under the influence of the sword, seizing control of the kingdom they had built together and naming it Regal Hartfort, and ruling with the proverbial fist of iron and heart of steel. He would let no-one else touch it, naming it ‘Gift of the Gods’ and caring for it with more devotion than he did himself. He was not a popular ruler; and he must not have been very happy himself, for he fell on his own sword when he was only forty-two years old. He was buried hurriedly and without great ceremony in a shallow barrow, along with his sword and a few oddments to be carried into the afterlife; no mourners turned up to his funeral. His young son, Hamund, took his place, and after a slightly shaky start turned out as a much fairer and more popular ruler than his father. Hart’s barrow, built without care, has since collapsed, and all inside - including the sword - lies just beneath the surface, waiting to be uncovered by an unwitting traveller. The sword, in particular, is straining, willing, waiting for just this to happen.
Its power is to bring out all the worst characteristics of its bearer, whether it be laziness, greed or even bloodthirstiness. It gets a hold on the mind of its owner, and before long owns them, so that it cannot be given up or cast away unless it be as soon as it is found. And, because of some ancient enchantment, it is always strong and sharp, though it can be chipped, corroded or broken. Its pommel is rough, hard leather, scorched from the force of all the magic piled into it at its creation; but its blade is quite plain and unadorned, if rather scratched and chipped. People who spend a long time in the same room tend to get the uncomfortable feeling that it is watching them, perhaps sizing them up.
This sword brings out the worst characteristics of its bearer, and cannot be given up of free will - though it can, with difficulty, be stolen or broken. It increases significantly the fighting skill of its bearer: it always moves to block and parry with the speed of a striking adder, though any who stop and look closely might notice that the sword seems to be going first and dragging the arms behind it. This sword is always sharp and strong (no matter how chipped or corroded it gets).