Feathered Serpent was the first game developed for the Gameslayer. It uses a function of "pain synthesis" allowing players to feel sympathy for the avatar in-game. This is later revealed to be making real people go through the replica level, get injured, be filmed and the recordings fed into the game system. Alex played it at a conference in London and was about to beat the first level on his first try when Damian Cray forced him to mess up. In a later chapter, Alex was forced to go through a replica of the game's first level in real life, Alex almost passes the level when he pretends to be dead. When the area is clear Alex escapes Feathered Serpent (Real life replica).
The Aztec god Quetzalcoatl's name means "Feathered Serpent".