As far as the origin of the concept is concerned, iI think only Hiro Mashima can tell!
Not only Assassins Creed but many other games have this kind of concept.
Its It's actually a very simple concept where uyou picture yourself as a wanted person and tryingtry to hide in the crowd around you
Hiro mashima has.
Hiro Mashima just made it more exciting by cloning the contestants and making it way more difficult to find the right person.
So what iI can answer is that he must have combined the concept of Hiding and the Conceptconcept of Shadow Clones from Naruto!