It can be found in the deepest chamber of «Jötunheimr», «ALO»'s most difficult field until player Kirito's party managed to acquire it. Contrary to popular belief, «Excaliber» cannot be obtained as a quest reward, as the quest Þrym and the frost giant generals give the «Fake Sword Caliburn» instead.
The NPC «Queen of the Lake» Urðr requests players to remove «Excaliber» from the «Plinth of Þrymheimr».
«Excaliber» was forged by the god of blacksmith Völundr. King of the Frost Giant Tribe «Þrym» once transformed into a wolf and infiltrated «Jötunheimr» to steal it. He then threw «Excaliber» into «Urðr's Spring», the center of «Jötunheimr» where it impaled the Tree of Life and cut off the source of energy. When the lake froze, and the ice dungeon was formed the Excaliber was trapped at the bottom of the ice structure.
The Spelling of "Excaliber"
The traditional spelling of the sword across most text is generally "Excalibur", with a "U". Sinon, who was head librarian during middle school and thus read a large number of books and noticing this, brought up several points regarding this, and wondered about the meaning of "caliber" from the gun-related meaning (gun's barrel diameter) to the meaning of "a man's capacity", or "a man with high capability." In the end, the discussion was interrupted regarding Kirito's capability to treat everyone due to his payment (compensation) from the government, and he resolved to never use Excaliber for personal gain as it contained the 'caliber' of himself and his companions.