...Kind of a pointless premise.
He's strong enough to fend off a group that can defeat his master, but he's not ditching guard-duty?
If he can freely leave the cave, why didn't he until he found the cleric?
If he can transform into a human, what was the point behind the sentiment: "nobody wants help from a demon"?
It was more interesting to find holes in this odd weave than actually reading it.
A very bizarre choice to translate this subpar story.