- "This is C.C. dash 10 slash 994."
"Commander Grey, the time has come…execute Order 66."
- ―CC-10/994 receives orders from Palpatine
Grey fought under Depa Billaba with captain Styles and Depa Billaba's padawan Caleb Dume. Grey was leading the column with Master Billaba and captain Styles when an explosion went off killing many of his men, droids then began to attack the remaining clones. Grey survived the following battle and with the help of the rest of the clones and Billaba, they forced the separatists to leave Kardoa.
During the Clone Wars, Grey fought under Jedi Master Depa Billaba and her Padawan Caleb Dume during the battle of the planet Kaller, in which the Republic defeated the Confederacy of Independent Systems. After the battle, Grey and Clone Captain Styles accompanied the two Jedi to see the Kalleran Gamut Key. Billaba informed the Kallerans that the Separatists would no longer trouble them, but the natives claimed they saw no difference between Separatist and Republic occupation. Dume, Styles and the Commander became angry at the Kallerans, but Billaba remained calm and informed Key that the Republic forces would spend the night in fields nearby. While camping later that night, the two clones and the two Jedi sat together and discussed why Billaba had not said anything to the Kallerans who compared the Republic and the Confederacy. Grey and Styles strongly disagreed when Billaba said she did not agree with Jedi taking up the rank of general, but were amused when they learned Dume had been infamous for asking to many questions during his time at the Jedi Temple on the planet Coruscant. During the discussion, Grey was contacted by Supreme Chancellor Sheev Palpatine and told to commence Order 66, the execution of the Jedi.
Unknown to the clones, it just so happened that Billaba had begun meditating and received a Force vision of the deaths of her fellow Jedi, then warned Dume of the danger. By the time the clones started aiming, Billaba told Dume to run, already on her feet and igniting her lightsaber.
Billaba and Dume ended up killing clone after clone. Due to this, Grey ordered the others to surround them and Billaba quickly realized that they could not win against nearly an entire battalion that was going to cut off all escape routes. She told Dume to run and he did as he was told.
Grey ordered concentrated fire on Dume, but he deflected the ones that didn't miss, so Grey instead ordered Styles to cut him off and hunt him down. Billaba shouted to Styles and turned toward him, intending to use the Force on him, but this left her open to Grey who shot her in the back. Having fallen forward to the ground, Grey and two other clones repeatedly fired on her, much like as had happened to Master Aayla Secura.
After Order 66Edit
In the following days, Grey and Styles continued to search for Caleb, but lost his trail when he radically changed his appearance and left Kaller. In reality, Dume had simply started working alongside the Kalleran smuggler, Janus Kasmir. After a job gone wrong resulted in the pair getting caught, Kasmir immediately sold out the fact that Dume was secretly the escaped Jedi Padawan, and seemingly traded him to Gamut Key's security in exchange for his escape. Grey and Styles were able to confirm for Key that the boy was, in fact, the Padawan they had been hunting for, and they ordered the Kalleran to hold him in a cell until they could leave the Imperial Garrison at Plateau City to take him in and execute him for treason within the hour. Shortly after their message, however, Kasmir had a change of heart and broke Dume out of his cell, escaping Kaller and intending to travel planet to planet across the Outer Rim.
Grey and Styles maintained a careful pursuit, always remaining just one step behind Dume and his new friend. They would finally catch up to the pair when they landed on the planet Lahn, where they intended to trade stolen spice to acquire a second ship. While Caleb went to negotiate with the buyer, Kleeve, Grey ambushed Janus and held him at gunpoint, demanding to know where the Padawan had gone. While Kasmir claimed that he had ditched Caleb as soon as they left Kaller, Grey remained skeptical, an exchange Caleb overheard, prompting him to flee. When Caleb never showed, Grey arrested Kasmir anyway, and began searching across Lahn for Caleb's whereabouts. When Dume convinced Kleeve to take him to his ship and allow him to escape, the pair were ambushed by Grey's Clones, and Styles was able to knock the Padawan unconscious, taking them both prisoner. 
While transporting Caleb back to Kaller aboard their Gozanti-class cruiser, Grey and Styles were finally faced with the task of putting an end to their former friend. Caleb pleaded for his life, reminding the clones how much they used to look up to Master Billaba and suggesting to them that it was Palpatine, not the Jedi, who had betrayed the Republic when he created the Empire. While he was unable to convince the clones not to kill him, Caleb did manage to buy enough time for Kasmir and Kleeve to catch up to the Imperial freighter. Caleb Force pushed the clones and remotely activated the airlock, escaping into the vacuum outside. After managing to return to the bridge of the freighter, Grey began to have doubts. Despite having sufficient firepower to destroy both the Kasmiri and Farbrooke's Hope, Grey could not help but wonder why the clones had so blindly obeyed Order 66. He brought his concerns up with Styles who disagreed, seeing Caleb only as a traitor to the Empire. When his protestations went unanswered, Grey decided to shoot the ship's controls with his blaster rifle, crippling the freighter and allowing Kasmir and Kleeve to destroy the ship with both Grey and Styles still on board.
Behind the scenesEdit
- Kanan 8: First Blood, Part II: The Towers of the Temple
- Kanan 9: First Blood, Part III: The Canyons of Kardoa
- Kanan 10: First Blood, Part IV: The Mesas of Mygeeto
- Kanan 11: First Blood, Part V: The Fog of War
- Kanan 1: The Last Padawan, Part I: Fight (First appearance)
- Kanan 2: The Last Padawan, Part II: Flight
- Kanan 3: The Last Padawan, Part III: Pivot (Mentioned only)
- Kanan 4: The Last Padawan, Part IV: Catch
- Kanan 5: The Last Padawan, Part V: Release
- Kanan 6: The Last Padawan, Epilogue: Haunt (Imagination)
- Kanan 12: First Blood, Epilogue: The Ties That Bind (Appears in flashback(s))
- Star Wars Rebels – "The Lost Commanders" (Indirect mention only)