~scratchnloved

There is a boy, living in a monestary. The boy is special, in that he can ONLY be killed by his own stupidity. The boy is very bright, and does not make mistakes often, even the minor sort. Growing confident in his powers, he decides to try his hand against a demi-god, an immortal.

He approaches a senior monk for advice, a man known for being a great riddler. The man offers him a weapon to slay the god. The weapon is a blade that can only kill those that cannot be killed (if you know what's wrong already, good for you ^^).

The boy confronts the god, confident in the weapon he holds. He swings the blade at the demi-god... and nothing happens. while the boy is gaping at the blade, the god plunges his scimitar up&under his ribs, killing him, for it was by his own folly that he confronted the beast.

My question for you:
Why did the blade not slay the demi-god?