1. Final Story Idea - Fantasy Dystopia, Theme: Happiness
A human scientist sells his soul to a demon in exchange for not dying of illness. With help of demonic spells, he builts a device that is able to extract the 'fantasy streak' from creatures that live hidden amongst people.
The scientist extracts the streak to power up a rapidly growing human utopia which leads to chaos in the lands of fantasy creatures.
They are the ones responsible for keeping the balance between two worlds but without their souls they can no longer maintain the harmony and that's when both worlds start collapsing.
It will be the hero's and his sidekick's goal to bring the balance and happiness back to both human and fantasy worlds.
2. Villain's demonic device (ideas):
Few silhouettes showing what the machine could look like. Each of these has an 'entrance' and 'exit' for fantasy creatures to walk in, get their 'souls' extracted, and walk out. Silhouettes of a flame represent what has been extracted, nr.2, 4 and 5 could also have a spot in which a viewer would see floating bodies of captures creatures.
Few silhouettes taken a little bit further: