Byouri wields DM

Kihara Byouri.

She has often been called an aunty, but she’s a big sister wearing pajamas… What age will the so-called 'aunt' in light novels nowadays be? This is a character who liked to play sick, full of mysteries, and also a boss character born from the Japanese tradition of transformation. I like a powerful foe that’s tough to beat and something I can use to rest my back on, so her trait was the phase adjustment to deliberately show that she couldn’t stand up. It’s this reason that Kihara Kagun would keep his guard when around her. This time, she used the power of the #2. But even without using his power, she could just use the knowledge and skills of a Kihara and modify her own body rampantly.

In the end, Kihara Byouri was basically formed from the change of phase with the anticipation of the attack from the science side. So if she was attacked by something out of science, that battle strategy which required transforming a few times and slowly becoming stronger wouldn’t work.
- To Aru Majutsu no Index NT4 Afternotes