The Beautiful Sword is a melee blade found at the Lake in the earlier part of the game. Its base power depends on the corruption of the champion. So long as they have low corruption, it is the strongest weapon in early game-play.
Beautiful Sword While walking along the Lake, the glint of metal catches your eye. You drop into a combat stance, readying your weapon for another fight. Your eyes dart about, searching for the source of the light. You feel rather foolish when you locate the source of the reflection. It came from a sword lodged hilt-deep in the trunk of a tree. You relax a bit, approaching the odd sight to get a better look.
The tree is thick enough to encapsulate the entire blade. Nothing protrudes from the far side at all. In another odd twist, there is not any sap leaking around the undamaged bark that surrounds the sword. The hilt itself appears made of bronze, with gold inlays along the outside of the handguard. Looking closer, you realize they portray a stylized figure battling a horde of demons. The handle is wrapped tightly with rugged leather that still looks brand new in spite of how long this sword must have been here for the tree to grow so thoroughly around it.
This beautiful sword shines brilliantly in the light, showing the flawless craftsmanship of its blade. The pommel and guard are heavily decorated in gold and brass. Some craftsman clearly poured his heart and soul into this blade.
Spoiler:If the Demon Factory's valves are destroyed as opposed to shutting down the controls, the Beautiful Sword will no longer be obtainable. Instead, the champion will note a rusted sword lodged in a dying tree. This only occurs if the sword has not yet been taken.
The Beautiful Sword may be a reference to the legendary blade Balmung which was embedded in a tree by the Norse God, Odin.
It also likely has inspiration from the Arthurian story of the sword of the stone, given that its coding refers to the Beautiful Sword as a sword in a stone.
Contrary to popular belief, the Beautiful Sword is not the strongest weapon. The Scarred Blade, the corrupted version of the Beautiful Sword, is, and the Jeweled Rapier comes after that. As these are both later-game items, however, the Beautiful Sword is one of the strongest early-game weapons.
Helia has a chance to mention a legend detailing the backstory of this weapon, if she's a lover and you have finished Tower of the Phoenix
Weapons are equippable items used to boost attack, among other effects.