A long time ago in a galaxy far, far away....
Rex was born in 32 BBY.
Captain Rex is the best-known clone trooper of the Clone Wars. He led the 501st Legion at Anakin Skywalker's side and was a steady mentor and close friend to Ahsoka Tano. His fighting took him from Christophsis and Teth to Ryloth, Geonosis and Saleucami. On Saleucami he let the deserter Cut Lawquane stay with his family, the first sign that Rex would think for himself. Serving under the treacherous Pong Krell on Umbara shook his blind trust in orders, and the death of his friend Fives, who had uncovered Order 66, led Rex to find the control chip in his own head. When the order came during the Siege of Mandalore, Ahsoka removed his chip and the two escaped the purge together. Rex then worked in secret to free other clones, retired to Seelos with Wolffe and Gregor, and returned to the fight to help the Spectres and the Rebel Alliance. He trained Ezra Bridger, fought on Lothal and at Atollon, and as a rebel commander lived to see the Empire beaten at Endor.
Rex is grown as CT-7567, one of the first generation of clones made from Jango Fett's genetic template.
He is singled out for leadership, receives command and ARC training, is made a clone captain and is given Torrent Company of the 501st.
Rex fights in the battle that opens the Clone Wars. Afterward the 501st is expanded into a legion under Jedi General Anakin Skywalker.
Rex and Commander Cody catch the clone traitor Slick. Rex meets Skywalker's new Padawan, Ahsoka Tano, and is told to show her the ropes.
He holds the monastery against Asajj Ventress to protect Skywalker and Tano while they rescue Jabba the Hutt's son.
With Cody, Rex retakes Rishi Station from droid commandos. He brings the surviving rookies, Fives and Echo, into the 501st.
Rex helps ambush General Grievous's fleet and destroy the Separatist listening post.
After crashing with Skywalker, Tano, Aayla Secura and Bly, Rex helps defend the Lurmen village against Lok Durd's defoliator.
He is infected during the raid on Nuvo Vindi's lab on Naboo and survives. He then serves with Tano when she breaks the blockade of Ryloth.
Rex fights on Felucia, against Cad Bane above Devaron, and on Malastare and Coruscant during the Zillo Beast crisis.
He supports the attack on Poggle the Lesser's droid foundry.
Rex is wounded while hunting Grievous. He recovers on the farm of the deserter Cut Lawquane and decides to let him stay out of the war.
Rex serves under Jedi General Pong Krell, whose reckless orders kill many clones. He finally turns on Krell, who is revealed as a traitor.
He trains Saw Gerrera and the Onderon rebels in their fight against the Separatist-backed king.
Fives uncovers the inhibitor chips and Order 66 and is killed before anyone will listen. His death leaves Rex doubting the Republic.
Rex sees Tano framed for the Jedi Temple bombing and then walk away from the Jedi Order.
Rex, now a commander, leads 501st troops under Tano against Maul. When Order 66 is given, Tano removes his chip. They fake their deaths, bury the fallen clones, and part ways.
Rex secretly helps other clones escape the Empire, working with Clone Force 99, Echo and Gregor.
With his chip removed, Rex lives on a converted AT-TE on Seelos with fellow clones Wolffe and Gregor.
The Spectres find him, and Rex joins the Phoenix Cell, where he is reunited with Ahsoka Tano. He also makes peace with Kanan Jarrus.
Rex trains Ezra Bridger in combat and becomes a regular ally of the Ghost crew.
Rex, Wolffe and Gregor help defend Chopper Base against Grand Admiral Thrawn's forces.
Rex fights alongside the Spectres in the battle that frees Lothal from the Empire.
Now a commander in the Alliance, Rex fights at Endor, where the Emperor falls and the second Death Star is destroyed.