Mysteriously healed...

However, that's not why you can't shoot NPCs. Instead of being carbon-based life forms, like us, NPCs are ninjate-based life forms, making it impossible to shoot them unless they attack you.

 

so they're entirely composed of tiny little ninjas?
what about the eye door?
It can't attack you, and you ruthlessly kill it.

 

If you touch it, it hurts you. It simply has no other way of attack.
And they're not composed of tiny ninjas, the substance gives ninja attributes to them.

 

Wait.......

except for that time when you beat him with only one hp left.
then you auto-die.

is that ever true?