When a translucent humanoid creature gets his memory back, he sets out to become the worlds judge, jury and executioner based on his way of life, while dealing with a group of people that disagree with his ways and try to stop him at any cost

It might be beneficial to set the story after the events of the main character taking over the world, with him reflecting on his actions and trying to justify them to the audience.

Good and interesting idea, however, is there a motive such as a specific memory as to why he wants to "become the worlds judge, jury and executioner" - this may better your logline in establishing the event that happened and the action the creature takes as a response to the event.

I think "become the worlds judge, jury and executioner" could be a little simplified.

Other than that, really interesting idea and would like to see how this could turn into a short film!