Holy Thunderforce (3.5e Equipment)
From D&D Wiki
This massive falchion seems to have been crafted with the idea that function came first, and style was of minor importance. It has a bluish tinge on its silvery blade and pommel, with a simple, rectangular crossguard made of (or coated in) gold. The hilt itself is wrapped in a dark blue scaled leather that would have come from some sort of lizard or dragon. When drawn, it glimmers and flashes momentarily with blue-white light.
This sword has the powers of a large +2 holy shock adamantine falchion 2d10 of holy shock damage. By uttering a command phrase as a standard action, the wielder may cause the blade to glow with blue-white light, illuminating an area as if affected by a light spell. A similar command phrase ends the glowing effect. This effect may be used at will.
In the hands of a worthy wielder - namely a cleric, fighter, knight, paladin, marshal, warblade, or vanguard of lawful good alignment - this sword becomes a medium +5 holy shocking burst adamantine falchion, with the following additions. It is treated as a Large falchion for damage purposes, and so uses 2d12 to determine damage instead of 2d10. It remains the same weight as a Medium falchion, and is still treated as Medium for size penalties. It also keeps its light ability.
It is said that, in ancient times, a great hero appeared in a land ravaged by dark powers and their vile servants. With the help of his friends, he earned the admiration of his fellow humans, the friendship of the dwarves, and the grudging respect of the haughty elves. They each gave him a portion of their finest metals - adamantine, and mithral. He took these metals to the best smiths he knew, who alloyed them, creating a material with the hard strength of adamantine with the lightness of mithral. From this they forged three special items - a suit of fullplate, a heavy shield, and this sword. After the items were made, the hero took them to a temple of his deity, and with the aid of the priests, they were imbued with power from the heavens themselves. With the aid of these holy items, and his closest and bravest friends, he succeeded in driving the taint from his homeland, establishing a new and lasting society in the place of the fallen one. After serving his homeland faithfully for many more years, he and his old friends met back together, and set off into new lands, vanishing forever into myth. Only the relics of their adventures together remain, hidden in the wilderness, or stored safely in royal vaults and temple sanctuaries.