Sword Art Online is a smart anime about people trapped in an MMORPG. Now, MMORPGs have swords. Elaborate, pretty, deadly swords. Like the Elucidator, which blacksmith Tony Swatton was kind enough to bring into our world.
Kirito's unique obsidian blade was then, as it is customary, used to slash apart all kinds of items from melons to coke bottles. Take a look: