Attack on Titan: Shingeki no Kyojin

[KrayZ33]

As soon as you show me titans getting their heads severed off.

Not sure what this has to do with anything you said though. You are saying something completely different. You are making up an assumption that the sword isn't able to cut through a human's neck or head.

Remember, YOU are the guy that says the sword is obviously not special because it can't cut X, yet it's able to cut Y.
Not me.

Yet, the "it can't cut X" thing, was never shown, because we can clearly see that it's able to cut through human tissue and bone with ease. Add to that the velocity of them 3D-ing and the full body motion swings they use against titans etc...