HOLY SHIT!
This was amazing! I'm going to focus on one part so my brain doesn't melt. The plot twist (IF YOU HAVEN'T BEATEN THE GAME, DON'T FUCKING LOOK AT THIS. IT SPOILS IT.)
(Review time.)
Alright: Thing is, that Twist...was unexpected, completely. I was amazed at the fact that you are IN FACT a monster; I wondered why you weren't being attacked by the Goliath at the end, which sort of added to the surprise. And on top of that, at most, at the beginning; I wondered why the creature looked so old. Nearly human, and like a father.
...And that is what it was....