The GEAR of Eden: Sonic Blade

Sonic Blades are considered an archaic oddity. With CPTs equipped with targeting computers being commonplace, sonic blades are largely obsolete for combat and deadly to handle. Sharpness is absolute as the blade is made of sonic bursts and is therefore only a few molecules in thickness at any given moment.

Zerstorer's blade, however, also fires long range bursts.

Most blades have a phase angle worked into the sonic disruptions that creates a shimmering to show the extent of the blade. Zerstorer usually keeps his blade invisible, unless training someone. An invisible blade is as much a danger to the human wielder as it is to the defender. Zerstorer's finely honed senses allow him to sense the blade even when it is invisible.

Excerpt from The Veil of Eden

Of course, he is prudent not to carry anything which would resemble a knife, so he fashioned a sonic blade. When activated, the hilt emits knifing sonic waves forth which are capable of fracturing steel when attenuated. He may even choose the length of the blade or send forth a burst like a thrown knife. And it is all inaudible to normal humans.

...

'Oh very well, a fencing lesson you shall have.' Zerstorer adjusts the phase angle of his sonic blade so that it becomes somewhat visible. 'I just hope you regenerate - not all of us do, you know.' With that, he lunges at Quay with a complex series of strikes. The attacks come so fast that from a normal human's perspective, the distortions from the sonic blade weave an odd Celtic pattern: the shimmering blade no longer appears to be straight. Amazing, considering the speed with which such a maneuver would have to be in order to create such an optical illusion in Quay's mind.