He got it after compleating the dungeon his father made for him. Its red cause its made from the blood of a demon.
The golden sword of battle is swallowed by a black hole in the episode The Real You. It is now (presumably) hidden somewhere deep within the Cotton Candy Forest.On his thirteenth birthday, in the episode Mystery Train, Finn discovers the root sword. This is used as his primary weapon until he and Jake go on a mission to search for the demon blood sword. It is unknown whether Finn kept the sword after it is replaced.In a confrontation at the tree fort, in the episode Play Date, Finn reluctantly snaps the demon blood sword in half when Kee-Oth forces him to. The broken remains were last seen in the treasure room.The grass sword (also known as the blade of grass) is introduced in the episode Blade of Grass. The cursed sword is bound to Finn's body until his limb is torn off in the episode Escape from the Citadel. The blade's present whereabouts are not known.Finn's most recent sword is accidentally created when a paradox arises. As the Finn sword is currently his preferred weapon of choice, it can be found on his person at most (if not all) times.
He got it for him and jake by using it to defeat the monster.
It is not known but it is seen that he had it for free by a wizard because it was cursed
the best way i know is to get a green backpack from a trooper.get an austronaut helmet get a knight sword and yellow hair and a blue shirt.
Finn Ohara goes by Finn, and F. Money.
Finn Taylor's birth name is Finn William Taylor.
Finn Ohara's birth name is Grifith Finn O'Hara.
Finn Gesner's birth name is Finn Harry Gesner.
Camila Finn's birth name is Camila Caroline Finn.
Carina Finn's birth name is Carina Kathleen Finn.
Dan Finn's birth name is Daniel Anthony Finn.
Jack Finn's birth name is Anthony Jack Finn.