The 100 years after the Great Calamity, while Link slept, were called the Age of Burning Fields. While the Champions were making preparations to battle Calamity Ganon, Ganon reappeared and devastated the Kingdom of Hyrule by taking control of the Guardians and the Divine Beasts. Upon their discovery, King Rhoam decided to excavate them.
This drove a search for the fabled ancient Sheikah relics: the Guardians and the Divine Beasts. One hundred years before the events of the game, King Rhoam Bosphoramus Hyrule became aware of the prophecy about the inevitable return of Calamity Ganon. Later, they will be able to fire multiple lasers in succession, with the first hit damaging Link and subsequent hits stunning him. However, striking a Guardian can cause it to shoot a laser without the need to lock on. When a Guardian spots Link it will lock on to him with its laser attack.
Since Guardians are possessed by Calamity Ganon, the Master Sword becomes more powerful when near these enemies. Ancient Armor provides higher protection against them, as does Midna's Helmet (acquired via DLC). Guardians are particularly vulnerable to the Master Sword and "Ancient" or "Guardian" weapons such as Ancient Arrows and Guardian Swords. Link can cause extra damage and prevent the laser charge by shooting its eye with an arrow. Guardians are resurrected during Blood Moons, despite being mechanical. These extremely hostile automata can destroy an entire town alone with their devastating laser, which can kill most creatures in a single hit. Guardians are enemies from The Legend of Zelda: Breath of the Wild. I've been researching ways to take them back." - Robbie
However, when the Calamity struck, they were stolen away. For many years, the Guardians were kept below Hyrule Castle. Ancient Gear Ancient Screw Ancient Shaft Ancient Spring Ancient Core Giant Ancient Core " The Guardians are self-guided weapons built to fight Calamity Ganon and developed by our Sheikah ancestors.