disguise break

If Unabara had abandoned his obsidian knife and rethought his strategy, he might still
have had a chance. Unfortunately, he decided he would wipe the dirt off of it. Of course—
given the choice between a fifty-fifty bare-handed brawl and magic that would let one win
for sure, anyone would choose the latter. He only needed to wipe it off a little bit—but that
was the temptation, which defeated him.
It delayed his reaction to Kamijou, who was right next to him.
A dull sound ripped through the air. The obsidian knife, with which he had persisted until
the end, flew from his hands as he fell backward.

***

August 31, 12:36 PM.

Kamijou looked down at Unabara Mitsuki, lying on the road.
With a glass-breaking noise, the skin on the part of his face where he had been punched
shattered to pieces. The face of the magician beneath looked even younger than Unabara,
and his complexion seemed darker. It was almost like someone had forcefully torn off a
sunburn—fragments of his face still stuck. It was uncanny.
“All right, then. Answer me this,” began Kamijou, breathing heavily. “Why did you decide
to change into Unabara Mitsuki, of all people?”

- Toaru Majutsu no Index Volume 5, Chapter 2 Parts 15-16