When "" was known as "Metal Gear Solid: Rising", former producer Shigenobu Matsuyama hinted that Raiden's past as a child soldier would be elaborated upon and his weaknesses as a human would be explored. Matsuyama wanted Raiden to have as strong a role in the game as in "Metal Gear Solid 2", leading him to become its main character. Director Mineshi Kimura wanted Raiden to be able to move the way he did in the "Metal Gear Solid 4" trailers, wanting to show "the stealth of the sword, and the strength of not even losing to the gun, and the fear and power you have with this blade". Matsuyama said they would focus on Raiden's strong will and physical strength so he would be enjoyable to control. Raiden's design was changed during the game's development, leading to different promotional images of him. Following the game's reboot into a spin-off, developers stated that while Raiden "has grown up" in comparison to previous "Metal Gear" games, he is still conflicted with his life as a child soldier in the First Liberian Civil War, leading him to become a "dark hero". Shinkawa designed Raiden's new body to emphasize his dark heroism, contrasting with his "Metal Gear Solid 4" persona. Shimkawa later discussed with Platinum Games' Kenji Saito about including his quasi-human look. Raiden's loss of an eye also represents his transformation across the story while also comparing him with the previous antagonist Solidus Snake. Tamari also explained that the cybernetic functions Raiden has was based on research led by the University of Texas. In response to complaints that "Rising" appeared to contradict Raiden's ending in "Guns of the Patriots", the Kojima Productions staff said the game would explain what happened with Raiden's life. While Steven Armstrong was the game's final antagonist, the character of Jetstream Sam was developed to be Raiden's rival, something Shinkawa and fellow designer Kenichirou Yoshimura worked together to make both of them contrast each other through their visual appearances.