The front end of Kihara Byouri's fingers expanded out like an airship. They became as large as oranges. If there was a need for another comparison, it would be roughly as big as a toddler's scalp.
[...]
After that, that inexplicable power was activated. Kihara Kagun was involved in a rather destructive explosion.
[...]
The gray dust was scattered about. Kihara Kagun, who should have been blown to bits, was standing with all his limbs intact. His coat and shirt had all been blown away as he stood in the -20 degrees region with his upper body naked. However, his upper body wasn't bleeding at all, just like before.

Toaru Majutsu no Index New Testament vol.4 main.31