According to Yasushi Adachi, the original idea for the game was a side-scrolling action game with various monsters. When considering what would appeal to a global audience while creating the concept for a monster game, he "ultimately felt that a fighting game with ninjas and samurais, which represented distinctly Japanese characters, would do better than just monsters", and changed the concept accordingly. Gen-An Shiranui is the only surviving character from the initial concept.
Contributed by DrakeVagabond