Immediately afterwards, all of the thick trees in the area were sliced in two at waist height.
It seemed to have been a long blade using wind or something similar.
The blade had been several dozen meters long and it had been created by a single card ripped from a set of flashcards held together by a metal ring. The card said “Wind Symbol” in yellow writing
[…]
The traces of damage were interrupted around where Fenrir stood.
A different color was mixed into the pure white of the snow. A number of black cracks had appeared as if space itself had been directly torn. One of those had “bitten” the wind blade.
“I don’t even need my canine teeth for this. If I release just my central incisors or lateral incisors, I can tear you to pieces right away.”
The sound of something breaking rang out.
The wind blade did not disappear or break. It was swallowed.
The cracks disappeared like the surface of clay being smoothed over with water. That long blade was swallowed up by those disappearing black cracks as if it was water being sucked down the drain of a pool.

Toaru Majutsu no Index New Testament vol.8 ch.4 pt.9