“Your main body supposedly has a few flesh-and-blood organs left in it. Did you move them away into the floor just before I attacked?”
“Well, what do you think? Did I move my organs out of the way at the last second or did I just remake all of them? Were the organs ever in that body to begin with? Are they in this one now? Maybe they’re scattered throughout the city and connected by thin strands of Dark Matter. And of course, would it even do any good to destroy my flesh-and-blood organs now?”
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They could destroy him, but it would be exceedingly difficult to be sure they had killed him.
And if they did not kill him, they could not stop him even if they blew off his arms and legs or crushed his organs.

Toaru Majutsu no Index New Testament, vol.6 ch.7 pt.9