Captain Rex is almost without a doubt the most popular clone trooper in the Star Wars universe, with the beloved character stealing scenes in Dave Filoni’s Star Wars: The Clone Wars and Star Wars: Rebels and most recently in Star Wars: The Bad Batch on Disney+. Captain Rex has stuck with Anakin Skywalker, Obi-Wan Kenobi, and Ahsoka Tano through thick and thin, and his importance in Star Wars is unparalleled.

Who is Captain Rex in Star Wars?
According to Wookieepedia:
Rex, formerly designated CT-7567, was a veteran Clone Captain, Clone Commander, and Advanced Recon Commando who commanded the Grand Army of the Republic’s famed 501st Legion of clone troopers during the Clone Wars. Rex later served as a captain and commander within the Alliance to Restore the Republic during the Galactic Civil War.
Rex participated in many battles over the course of the Clone Wars. As the captain of the 501st, Rex served as second-in-command to Jedi General Anakin Skywalker, whose bravery and unconventionality in battle he came to share. In addition to being a close friend of Skywalker, he also became friends with Skywalker’s apprentice, Ahsoka Tano.
CT-T567, later given the nickname “Rex,” was like his fellow clone trooper, created from the genetic template of Jango Fett (Termura Morrison), a Mandalorian bounty hunter first seen in Star Wars: Episode II – Attack of the Clones (2002). Boba Fett and Omega from The Bad Batch were also created from Jango’s DNA, presumably with the hope of the Kaminaons creating the “perfect” soldier.
Rarely showing any flaws and continuing to improve in perseverance, integrity, and grit, Captain Rex is promoted to Commander in season seven of The Clone Wars, when the Grand Army of the Republic plans to invade the planet Mandalore with Ahsoka Tano, in what would later be known as the Siege of Mandalore.

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While a very important trooper in the Clone War era, Captain Rex adopted a less rigid approach as the Clone Wars continued and began looking at the bigger picture of life towards the end of the war. Referring to his fellow soldiers as “men,” not “clones,” Rex’s priorities were first and forever his clone brothers. He loved many as his own kin and was disgusted with Clone Sergeant Slick’s betrayal of the Republic during the Battle of Christophsis.
Rex was appalled by Order 66 — after his inhibitor chip was removed with the help of Ahsoka Tano — and the killing of his men while defending himself and Tano.
Many treated Rex more like a brother than just a friend, forming a close relationship with Jedi Master Obi-Wan Kenobi, Anakin Skywalker, and Ahsoka Tano. He was the #1 choice for any tough battle, as the Republic knew time and time again that Rex would get the job done the most ethical and humane way. He was, by far, the most important clone trooper in the clone wars.

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His character was enigmatic, as fans grew to love the clone captain more and more through The Clone Wars and Rebels, which featured an older Rex who survived Order 66 and remained a low profile throughout the galaxy.
Origin of Captain Rex in the Star Wars Universe
Like his fellow troopers, Captain Rex was created from the genetic tissue and DNA of bounty hunter Jango Fett on the planet Kamino.
Unbeknownst to the Jedi, a massive order of an army had been made for the Grand Republic by a thought-to-be-dead Jedi. This, for whatever reason, didn’t raise any red flags for the Republic or F, so they adopted these clones as soldiers for their oncoming war with the Separatist Alliance (Confederacy of Independent Systems).

What battles did Captain Rex stand out in to help him get promoted to Commander?
Clone trooper Captain Rex fought in essential battles of the war, and his resumé is almost never-ending. Still, the Battle of Christophisis, Test, Saleucami, Lola Sayu, Ringo Vinda, and Rishi Moon are the most important.

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Rex’s leadership skills were put to the ultimate test at the Battle of Umbara, when he was forced to lead the 501st Legion under the aggressive Jedi General Pong Krell, a secret Separatist agent. Krell forced him to readopt his old, rigid adherence to follow orders, but he questioned his purpose and orders.
Appearances in Star Wars movies
Captain Rex has yet to make his live-action debut in a Star Wars series on Disney+, but George Lucas confirmed that you could see a much older Rex for a brief moment during the Battle of Endor with Han Solo (Harrison Ford) and Princess Leia (Carrie Fisher) in Star Wars: Episode VI – Return of the Jedi (1983).

When Solo gets the attention of a few stormtroopers on the moon planet of Endor, he leads them around the corner of their base entrance. Waiting for them is a squadron of rebel troopers, including Captain Rex himself.
What began as a fan theory became an official confirmation by Star Wars creator George Lucas himself, stating that the older gentleman with the white beard is Captain Rex.

Captain Rex is a crucial part of animated series The Clone Wars and the Skywalker Saga overall. Without his presence and influence over the pivotal battles between the Republic and Separatists throughout the prequel trilogy, the Star Wars saga as we know it would have been very different.
Rex was, in fact, not originally planned for Star Wars: The Clone Wars, but creator George Lucas felt that an important clone trooper was needed as one of the main characters in his animated series, and the rest is history.
Is Captain Rex your favorite clone? Let us know in the comments below!