Kojima received much fan mail; one letter from a girl stated she did not want to play a game with an old man. Kojima took this into consideration; he and his team designed Raiden to be more appealing to women. Designer Yoji Shinkawa said he and the other character designers took much inspiration for Raiden's appearance from the "bishōnen" archetype. Because Raiden was a new character, the staff designed him carefully, giving him white hair to symbolize his introduction. Shinkawa also said Raiden had an overall feminine appearance. His outfit—the Skull Suit—was difficult to design until the staff decided on a "bonelike" concept. Shinkawa wanted to make Raiden sexually appealing, emphasizing the tightness of his clothing. The design of Raiden's aqua-mask was inspired by ancient mystical ninjutsu, where the ninja bites a scroll in the mouth during magic transformations. Raiden's final duel with the boss Solidus Snake was revised in the making of the game. Originally, to defeat Solidus, Raiden must cut off both his mechanical snake-like arms, then he must attack Solidus' back and sever the back bone vertebra connection, rendering Solidus no longer mobile. Following this, Raiden would finish Solidus by decapitating him similar to samurai fashion. The scene was rejected and instead Raiden would slice Solidus' stomach, another idea taken from samurais. However, this concept was also scrapped to simply Raiden slicing Solidus' vertebral column with the boss falling from the area to give the idea he could not accept his defeat.