Kihara Kagun ignored the distance between them as he casually stepped into the darkness. He formed a handgun gesture with his right hand and pressed his index finger against the center of the mysterious villain’s chest.
He did not need any fancy weapons or products. The theory alone was enough.
“A mere 80 millivolts,” a voice whispered.
Almost like an afterthought, all the glass instruments shattered.

[…]

“That is only about 1/20 of a single 1.5 volt battery. A human’s bioelectricity is no more than that. The heart, brain, muscles, nerves, and every other organ function based on an electrical potential that would generally be seen as a rounding error. There is no need to use the other world here.”
“…”
“Do you understand, newcomer?”
She had no chance of doing anything.

Toaru Majutsu no Index Kagun SS