While holding her in place, Kamijou shouted, “You aren’t Mikoto, are you!? Who are you!?”
He heard a cracking noise.
The skin of whoever was taking on Misaka Mikoto’s form began to split open around the neck where he was grabbing them. As Kamijou watched on in shock, the cracks spread farther and farther. And it did not only spread across her entire body. The cracks spread across the entirety of Misaka Mikoto’s form, including the coat and hair decorations she was wearing.
“I’m sure you have a pretty good idea,” said the person as the lips moved despite a portion of them being missing thanks to the countless cracks.
In the next moment, the destruction exceeded a sustainable level.
The image of Misaka Mikoto shattered and a boy with long, blond hair, white skin, and a feminine look appeared from within.

Toaru Majutsu no Index New Testament vol.5 ch.1 pt.8