Kamijou was one of the closest ones to the scene, but he did not know that a giant sword 30 or 40 kilometers long had been swung down. After all, the base of the sword, was so far away it was almost disappearing off the horizon. A sizzling sound could be heard coming from the sword. It wiggled back and forth and then slowly lifted up much like an axe being pulled out of a large tree.

“With something this big, aiming can be a pain,” Fiamma said cheerfully.

Kamijou trembled as the giant sword that could split a mountain range in two was once more casually lifted up.

[...]

He had corrected his aim and dropped the giant sword down from directly above. The Elizalina Alliance city was sliced in a straight line and the stone building Kamijou and the others were in took the brunt of the blow causing it to be almost completely smashed to smithereens.

A cloud formed.

The difference in air pressure created by the slicing of the atmosphere created something similar to a contrail.

That strike had affected the weather.

Toaru Majutsu no Index vol.20