He first appears within stasis in the Mysterious Lab, and is awakened by a battle between Hunters and Galleons, not knowing who he was or anything about his world. Pandora finds him and proclaims him as "Defective", explaining that she has to kill him. However, he grabs a gun from a fallen Hunter, fires on her, and escapes. He is knocked out while fighting Dogu the Giant.
He is later found by the Hunter Billy, who takes him to Hunter Camp, where he is given a Hunter's License and asked to help escort the Model A Biometal to Legion. However, Prometheus and Pandora attack the train carrying it, and the Biometal responds to Grey. They Megamerge, and the pair allows him to join the "Game of Destiny". Shortly after, Grey discovers the power of A-Trans after defeating the Pseudoroid, Buckfire (Diaburn in the Japanese version). Model A, though unsure of assisting Grey, decides to tag along for his own safety.
He is then given an invitation by the Sage Trinity to visit Legion, the most powerful organization in the world in order to inspect Model A. During his venture, he encounters four other Mega Men, Aeolus, Atlas, Thetis and Siarnaq, who wields the Biometals, H, F, L and P, respectively. He first fights against Atlas and manages to defeat her before she harvests the souls of a stray group of Raiders to Model W and in the process, breaks a cipher, revealing secret encoded data about the Model W. Grey then finally heads to Legion but is temporarily stopped short by Siarnaq, but is also defeated, resulting in another cipher, this time, showing a vague figured as well as a hint as to the creator of Model W, who appears to be one of the Sage Trinity. Though Model A is unsure at this point, Grey continues on ahead for the truth. The perpetrator appears to be none other than Albert, who is seen with several Model W fragments and escapes Grey's attack, but not before telling him he was 'made in his image'.
During his missions for Legion, Grey unlocks more ciphers after defeating the four megamen he met earlier while traveling to Legion. After completing the new destinations Master Thomas had added to the transerver, he then encounters Aile in the Quarries, along with a Model W. Grey demands Aile to step away from the Model W, but Aile refuses and Double-Megamerges with Model X and Model Z. She decides to challenge Grey for the Model W. After Aile's defeat, Grey unlocks the final cipher, revealing data of Albert's goal to combine all the Model Ws forming the ultimate Biometal, Ouroboros.
Later on, he discovers that he was made as an "Alternate body" for Albert, who created Model A, also known as Model Albert. After Grey has defeated Albert, he then collapses. Meanwhile, during the fight between Aile and the four Mega Men, Model Z insists that Aile has to go rescue Grey while he stalls the enemies. It is unknown whether Model Z Survived the fall of Ouroboros. After Grey wakes up at Hunters Camp and finishes his conversation with Aile, he and Model A go explore the world in search of their destinies.
Alt of
MegaCollection
Alt of
Gaud