Finn's swords

Finn's swords refer to the types of swords (and a dagger) that Finn has used throughout his adventures in the Land of Ooo.

Main swords
These are the swords that Finn had mainly used throughout the series.

Finn's golden sword of battle
The golden sword is Finn's weapon of choice throughout most of seasons one and two. The blade is dented, chipped, and dirty, likely due to a combination of overuse, poor maintenance, and the low-strength material properties of gold. Its hilt is black with some worn leather grip-straps and a red gemstone in the pommel (possibly a ruby). In "Business Time," the Businessmen polish and sharpen the sword, making this episode the only one in which the golden sword appears to be in excellent condition.

In "The Real You," the golden sword passes through the Bubble Creator and becomes four-dimensional. When Finn uses the 4-D golden sword to attack the black hole he created, Finn's golden sword is sent into the Candy Forest by the explosion. Finn is without a sword until "Mystery Train."

The golden sword, or one similar, is later seen at the end of "Fionna and Cake," when Finn and Jake are frozen in the Ice King's castle.

This design of this sword is the basis for the 24-inch toy version of Finn's sword, which is labeled as "Finn's Golden Sword of BATTLE."

Root sword
In "Mystery Train," Finn obtains the root sword (the name is non-canonical), which becomes his primary weapon. He finds the sword on the caboose of the train and uses it to attack The conductor. He next uses it against the Giant in the beginning of "Belly of the Beast." It is seen briefly in "Mortal Recoil," when Finn throws it at Ice King, "Conquest of Cuteness," and in "Jake vs. Me-Mow." He keeps it in a makeshift pocket on his backpack.

Demon sword
The Demon sword first appears in the episode "Dad's Dungeon." In the episode, Finn and Jake go to Joshua's Dungeon to retrieve Jake's family sword. At the end of the dungeon Finn finds it encased in locks and stone. He breaks it loose and uses it to fight the final monster of the dungeon. The sword is made out of Demon Blood, which causes Blood Demon to sporadically appear and plead to Joshua (and later, Jake, thinking he's Joshua) for the return of his blood. Blood Demon is easily banished away using the spell "Kee Oth Rama Pancake." In "Return to the Nightosphere," Finn spins it in front of the blood mist cloud, and hits Marceline with it, thinking she is Hunson Abadeer. In "Daddy's Little Monster," Finn can be seen holding it throughout the video files on Jake's "new video phone." In "Beyond this Earthly Realm," Finn uses it to slash one of the heads from The Dead One. In "Gotcha!" he uses it to save Lumpy Space Princess from the Mirror Finns.

Minor swords
These are the swords Finn has kept at the Tree Fort.

Steel sword
In the episode "Morituri Te Salutamus," Finn picks up a steel sword during his first battle in the Fight King's Arena; it is similar to his original gold sword. The hilt has a leather grip and the pommel has a purple gemstone with a tiny pink gemstone slit in the center. The sword itself is in very good condition. It is later seen again in the episode "Still."

Pink jewel sword
In "Slow Love" there is a pink jewel sword, with a hilt that is pointed on both sides and a pink gem on the bottom. The sword is seen slicing Finn's bed in half, but Finn has not been seen using it himself.

Katanas
Finn has two golden katanas in the episode "Slow Love." They are used by Finn when he teaches Snorlock to do sword tricks.

Loot Swords
Various other swords, daggers and other weapons can be found in Finn & Jake's treasure rooms and other rooms of the house, - though they are never used in the storyline and are presumably loot.

Temporary swords
These are the swords Finn had temporarily used and imagined.

Sword of the dead
Finn wields the sword of the dead to defeat Marceline's father in "It Came from the Nightosphere." Finn draws the sword from the Grass Lands before his battle and slits open the pods in Hunson Abadeer's gullet, which he is using to imprison the souls of Ooo. Finn drops the sword while reciting the incantation to open a portal to the Nightosphere.

Dual swords
While Finn is under the "control" of Fight King in the episode "Morituri Te Salutamus," he fights with dual swords that look like a single sword that was completely split apart from the tip of the blade to the pommel. When Finn is forced to fight Jake, he only uses one of them.

Crystal sword
In "Mortal Folly" when Finn, Princess Bubblegum, and Jake meditate, Finn is grown up in his imagination. The imaginary Finn has a new crystal sword in a back scabbard.

Dungeon sword
In "Dungeon," Finn uses a sword he found in the dungeon to fight off Eye Creatures, but the fiery creatures melt it shortly before Princess Bubblegum rescues Finn and Jake.

City of Thieves sai
Finn steals two sai in the episode, "City of Thieves" but they are taken by two angels at the end.

Dagger of chilled glass
When Finn and Jake learn ninja skills in "The Chamber of Frozen Blades" Finn creates the dagger of chilled glass using his ninja skills.

Dagger
Finn picks up a twisted, yellow dagger outside the windmill when he and Jake approach the "monster" in the episode "The Monster." It resembles a kris, an Indonesian dagger considered to possess magical powers.

Shark sword
In "King Worm," Finn imagined a sword that he planned to use to blast a hole in the wall. However, Finn never got to use it because he thought about a shark trying to bite off his face and unintentionally changed the sword's blade into one.

Trivia

 * The sword in the Adventure Time logo has never been used, other than in the promo video. However, a version of it was imagined by Finn while dreaming in "King Worm."
 * The yellow twisted dagger Finn used looks similar to Me-Mow's dagger.
 * Fionna (the gender swapped version of Finn) has a Crystal sword.
 * The Tree Fort has several swords strewn around it, though Finn and Jake never use these.
 * In the game Adventure Time: Hey Ice King! Why’d you steal our garbage?! Collectors Edition there is a stylus resembling Finn's golden sword.

Cultural references

 * Steam user M-NINJA made the sword a custom item for the Scout in the video game Team Fortress 2.