Someone has made Amnesia into Horror Novel???

[hollowleviathan]

I don't know what you mean by law obligations, a company is not obligated to pursue derivative works of their intellectual property.

Fan fiction is by definition unpublished freely distributed transformative product that is generally protected by the fair use laws in the US or equivalent elsewhere.

This book in particular 1. isn't even distributed, 2. and it's in Indonesia, so there's no incentive to pursue legal action, and I have no idea what Indonesian copyright law looks like.