Pikmin 3 went through several different phases. At first, it was originally intended for the Wii, but eventually moved up to the Wii U, with the developers removing some gameplay elements along the way.
These gameplay elements remain largely unknown, but one element that has been discovered was the presence of a fourth character. He or she is visible in early concept art, and it is said that the character wasn't removed until late in the game's development.
No video footage can be found of "Character D", as it never appeared in any trailers or demos. With the Wii U having been out for such a short period of time, many game hackers are still having trouble discovering the content of game files for Wii U games. Thus, there's no knowing if the character exists in the game's source code somewhere. The code could also be hiding various early gameplay mechanics. Until the secret is decoded, "Character D" exists merely in one frame of concept art, and is lost.
- Pikmin 3 Almost Had FOUR Characters. From NintendoLife. Retrieved April 21, 2015.