Del Toro wrote the Halo movie script. Does the Master Chief have a brother?

Among the myriad possibilities for live-action adaptations, there was a time when Halo was a possibility for a Guillermo del Toro film. According to a developer of the original game, the director once had an idea to have an evil doppelganger of the Master Chief in the hostile faction of the Flood.

In a recent video show, Halo: Combat Evolved environment artist (and Halo creator) Paul Russell mentioned an unfinished Del Toro Halo movie script, which contained an interesting plot detail:

"The Master Chief has a twin brother, and this twin brother joins the Flood, and the end of the film is a brother-brother showdown."

Other developers expressed disbelief at this plot setting, but Russel insisted that this was the idea the director presented to the development team:

"That's what Joey (probably Joseph Staten, the original screenwriter and CG supervisor of Halo) said at the time. Del Toro went to Joe's house and gave the idea to him. He also punched Joe in the arm and said, 'They are brothers! They are going to fight at the end!'" Russel said that he was able to confirm the existence of this story, but never mentioned it again afterwards.

Del Toro has previously said that he had written a script for the game with Game of Thrones screenwriter DB Weiss in 2006, but ultimately turned to filming Hellboy 2: The Golden Army.

"Halo" is currently being adapted into a TV series with Spielberg as executive producer and Pablo Schreiber playing the Master Chief, but no release date has been announced yet.