Forum:Finn's Demon Sword?

So I was drawing Finn with his Fathers sword and i began to wonder what does it do? It was guarded by a big giant monster and made out of demons blood. Shouldn't it do something? Has any interviews with Pen or someone else that works on Adventure Time said anything about it? In my personal opinion I think it might be able to harm the lich. Might have a property to kill deathless creatures.