Decayed Master Sword
The Decayed Master Sword is a melee weapon found in Tears of the Kingdom.
Tears of the Kingdom
The Decayed Master Sword is the first weapon that Link obtains in the game, found in the Room of Awakening close by him once he wakes up with the Zonai Arm for the first time. A downtempo variation of the "Item Obtained" theme plays when Link acquires it, signifying how it has been immensely damaged and nearly destroyed by gloom. It has a base power of only 1, and is effectively only used for two purposes: cutting the vines in front of Link so he may exit the room, and the cutscene after completing the Great Sky Island where it is sent backward in time to Princess Zelda, who receives it in the era of Hyrule's founding and is determined to repair it, ultimately doing so after becoming the Light Dragon and bathing it in sacred light upon her draconified forehead. The next time Link sees the weapon will be upon the Light Dragon, having been restored properly to the full Master Sword once more.
While on the Great Sky Island, it can be used in combat, but it runs out of energy fairly quickly and is only useful in this form when Link has no other weapon options. Upon descending to the Great Sky Island proper, Link will almost immediately begin finding Tree Branches, which are already an improvement in base power over the Decayed Master Sword. It is the only weapon in the game with no Hyrule Compendium entry, as it only appears in the game before Link can use the Camera on his Purah Pad.