Promises, Promises.On Rex's "birthday" (the anniversary of when he joined Providence), Agent Six reflects on the day he first met Rex. Years prior, Six and White Knight are partners working for Providence during its early days. During a battle against a gigantic mechanical EVO in Mexico, the EVO explodes and Six discovers a young Rex in its closed fist. After learning that Rex has the ability to cure EVOs, Six secretly brings him to Providence and shows him to then-research assistant Dr. Holiday. White Knight, discovering Rex's nature, orders that he be dissected using a machine that magnetically strips nanites from a host body, killing the host. Six and Knight battle over Rex, and in the process, White is trapped inside of the machine and nearly killed, until Rex deactivates it at the last moment. As a result, White Knight is stripped of all nanites but left alive, and is chosen to lead Providence as the only human on Earth who cannot turn into an EVO. White Knight reluctantly allows Rex to stay at Providence, but warns Six to kill Rex should he ever show signs of turning into the giant EVO again. In the present day, Six gifts Rex with a tantō, a ceremonial samurai blade, marked with a symbol of loyalty, stating that the two of them will follow the same path.