The first-available and weakest longsword in the game, the Rusty Longsword is an iron sword of exceptionally poor condition and capabilities. It is found on a skeleton by the door out of the room in which the Fateless One wakes up at the very beginning of the game. Despite its common rarity (white name), it is unique in that you will never receive a second one.
The Rusty Longsword is beyond any but the most basic of repairs; repairing it will still leave it rusty, and even the Acid Solution found in the inn at Ayten cannot remove the rust from it. However, its blade, among other parts, is salvageable and is somehow equal to any other Iron Blade upon such disassembly.
Components salvageable from it include: