Cassio Tagge, a male human officer of great rank, served the Galactic Empire throughout its reign. Born on Tepasi to the affluent and influential Tagge family, Tagge occupied the role of Chief of the Imperial Army. As a member of the Joint Chiefs of the Imperial Military, he possessed entry to the Imperial Palace's highest echelons. During the Galactic Civil War's initial phases, Tagge, then a General, stood against Grand Moff Wilhuff Tarkin and Admiral of the Fleet Conan Antonio Motti's ambition to orient Imperial military doctrine around the DS-1 Death Star Mobile Battle Station superweapon, where he functioned as chief of military operations.
Following the Battle of Yavin and the battle station's annihilation, Emperor Sheev Palpatine elevated Tagge to Grand General. As the new supreme commander of the Imperial military, he depended upon systems analysis and sought to refocus Imperial strategy towards leveraging numerical advantage. Despite successes in anti-piracy actions, his period in command was defined by a bitter conflict with Darth Vader, Dark Lord of the Sith. This friction led Tagge to increasingly depend on cyberneticist Cylo as his enforcer. However, Cylo's betrayal resulted in the Emperor losing belief in Tagge, which resulted in his demotion and, shortly after, his execution at Vader's hand.

Cassio Tagge, a male human hailing from Tepasi, was born into the House of Tagge, a noble and wealthy family that possessed and managed the Tagge Corporation. Within a year of the Galactic Empire's formation, the autocratic government that had supplanted the Galactic Republic upon the conclusion of the Clone Wars, Tagge enlisted and became an officer in the Imperial Army. TaggeCo also worked with the Empire, bolstering its authority and war machine. By 14 BBY, Tagge had achieved the rank of General and ascended to lead the Army. As Chief of the Imperial Army, he participated in the Joint Chiefs of the Imperial Military. He was seen as a competitor to Vice Admiral Dodd Rancit, who directed the Naval Intelligence Agency.
In addition to his army role, Tagge also held the post of commander of his personal starfleet. In 14 BBY, Tagge convened with the other Joint Chiefs on Coruscant to consult with members of the Imperial Ruling Council and the intelligence divisions of COMPNOR concerning the attacks undertaken by an insurgent group that had taken control of Moff Wilhuff Tarkin's private ship, the Carrion Spike. During that meeting, news arrived that the insurgents were attacking Imperial resources on Lucazec, which troubled Tagge because TaggeCo had operations there. He watched in anger as footage showed the insurgents destroying space and surface operations. The insurgents were eventually captured and put to death, and Tagge was among those who received recognition for his contribution to stopping the threat.

Shortly before the Battle of Yavin, Tagge was stationed on the Death Star, where he oversaw army operations as Chief of the Imperial Army with the rank of general. During a gathering of prominent Imperials aboard the Death Star, Tagge debated with Admiral Conan Antonio Motti, a fellow Joint Chief, who disagreed with Tagge's assessment that the Rebel Alliance, which had stolen the Death Star plans, posed a threat to the Empire and the Death Star. Motti dismissed Tagge's worries, stating that while the Rebels might be a threat to Tagge's fleet, they were not a threat to the Death Star. Tagge began to point out that the Rebels had been building and would continue to build support within the Imperial Senate, but was cut off by the arrival of Grand Moff Tarkin and Darth Vader, who announced to the officers that Emperor Sheev Palpatine had dissolved the Senate. Tagge was shocked by this news and openly wondered how control would be maintained without the bureaucracy, but Tarkin revealed that regional governors like himself would now have total control over their territories, with the Death Star's threat maintaining order through fear.
Tagge again argued that the Rebel Alliance was a threat to that plan because they had the technical readouts of the Death Star, which might allow them to find and exploit a weakness. However, Darth Vader claimed that the plans would soon be recovered. Motti again dismissed their concerns, saying that even with the plans and any technical data they had, any attack would be futile against the battle station. After suggesting that they use the Death Star, Vader warned Motti not to be proud of it, arguing that the ability to destroy a planet was insignificant compared to the power of the Force. Motti began to argue with and insult Vader for his failure to find the stolen plans and his devotion to the Force. Tagge watched uncomfortably with the other officers as Vader began choking Motti with the Force until Tarkin, who seemed bored, ordered Vader to stop. After witnessing Vader's display of power, Tagge glanced at the chair two down from his, which had previously belonged to Director Orson Krennic, and made eye contact with Motti. While neither said anything else for the rest of the meeting, Tarkin then addressed Tagge's concerns by claiming that Vader would soon learn the location of both the plans and the hidden Rebel base, after which the Rebellion would be quickly crushed along with any threat it presented to the Empire. However, Tagge no longer viewed the Death Star as the Empire's greatest weapon, and he instead began to believe that its greatest weapon was Darth Vader himself.
Despite Tarkin and Motti's confidence and arrogance in the Death Star's might, Tagge's fears were soon realized when the Rebels destroyed the battle station at the Battle of Yavin. Tagge survived the Death Star's destruction, having left the station to investigate Princess Leia Organa's false claims about an active Rebel base on Dantooine. During Tagge's investigation, his forces brought back a female individual who had been lurking around the perimeter and had greeted the stormtroopers openly. Tagge briefly questioned this individual about her motives, to which the individual claimed that she was simply salvaging any components left over in the abandoned base. Tagge became suspicious about her knowledge of the base's connection to the Rebels but ultimately came to the correct conclusion that the individual had no prior relationship with the Rebel Alliance. Despite this conclusion, Tagge decided that she was still too dangerous to let live. He then ordered her execution, which was then forced to be carried out by one of the stormtroopers under his command. This decision to use only one stormtrooper to execute the individual (whether made by Tagge or one of his sub-commanders) would prove to be faulty as the individual would quickly make her escape from the attempted execution and the planet.
After the Battle of Yavin, Tagge was praised by the Emperor for having the foresight to recognize the Rebel threat and weaknesses of the Death Star. As a reward, Tagge was elevated to the rank of Grand General and became de facto Supreme Commander of the Imperial Armed Forces, which would now be governed by his philosophy as the second Death Star was constructed.

Darth Vader was subsequently placed under Tagge's command due to his failure to protect the Death Star, and the two began working together to identify the source of increased pirate raids on the Empire's shipping. Vader stopped one of these attacks, disabling an automated CR90 corvette and returning it to Tagge's flagship, the Super Star Destroyer Annihilator. Tagge and Vader both agreed that the sophistication of the attacks suggested a well-supplied and smart group was behind them, and that a spy was likely feeding them information on Imperial shipping. Tagge was unconcerned with the level of attrition to the Empire's supplies by the attacks, noting that they were well within normal levels of unrest that could be expected after a disaster like the Death Star's destruction. However, he expressed disappointment at the amount of resources wasted in the construction of the Death Star, referring to it as "Tarkin's Folly," and wondered how many more Super Star Destroyers could have been built instead.
Vader countered Tagge by claiming that Tarkin had vision, while Tagge was more concerned with statistics and graphs. Tagge reminded Vader that he also had the command of the military, and that although his plans might not be as grand as Vader or Tarkin's, they were still effective. After lecturing Vader on the power of the fleet to crush any form of resistance through sheer size and firepower applied over time, he informed Vader that he planned to repair the pirate vessel so that it would return to its source. Vader noted that the pirates would surely destroy their station rather than risk further exposure, a point Tagge agreed with, and he then informed Vader that he would lead the team aboard the corvette aboard the station to recover the information they needed before that occurred. The Grand General then proceeded to lecture Vader on how their new arrangement was for the best, comparing himself to a skilled lightsaber wielder, with Vader as the lightsaber. He then informed the Dark Lord that he was also assigning Lieutenant Oon-ai to be Vader's adjutant, albeit one who would also be personally reporting back to Tagge.
After Vader successfully raided the pirates' space station, he returned to Tagge and complimented the Grand General on his plan and informed him that the pirates were being backed by the Crymorah Syndicate. Tagge was pleased that they knew who to target, but was stunned when he turned around and saw Vader carrying Oon-ai's body. Vader threw the lieutenant at Tagge's feet and claimed that he had identified him as the leak, noting that Oon-ai must have used his closeness to Tagge to steal the information, and that Tagge should choose his aides more carefully. In actuality, Vader had an astromech droid plant information in the pirates base that implicated Oon-ai in order to remove Tagge's spy from his presence and send a message to the Grand General.
In addition to his efforts to root out pirates, Tagge was charged with overseeing the Imperial expansion of the Outer Rim. For that purpose, he decided that criminal elements which had been left unchecked in the previous years would no longer be allowed to act with impunity. The only ones spared from Tagge's crackdown were the Hutts as a result of their newfound alliance with the Empire. As part of this new campaign, Tagge sent Vader to destroy the Son-tuul Pride, a major competitor of the Hutts and the masters of the Son-tuul underworld. Vader successfully destroyed the Pride by using one of their smugglers as an agent to track down their headquarters. Their horded stash of credits became Imperial property and, per Tagge's decree, were to be immediately transmitted to Imperial vaults.
After the Son-tuul Pride fell, Tagge then concentrated on crushing the Plasma Devils. He was also assigned to deliver missions to several new agents selected by the Emperor: cyborgs created by Cylo. His remaining task force was placed under the command of the Astarte twins. General Karbin was sent to capture Luke Skywalker and Tulon Voidgazer was assigned to overlook certain research problems. Vader was instructed to track down the people behind the theft of the Son-tuul Pride's fortune and punish them. Tagge, who wanted the credits recovered to fund the construction of a new Super Star Destroyer also assigned Inspector Thanoth to be Vader's adjutant.

When the mining world of Shu-Torun descended into civil war due to the Ore-dukes' refusal to honor the Empire's taxing tithes, the Emperor ordered a full military intervention to defend the Imperial-backed government led by Queen Trios. Vader was given command of the military force sent to Shu-Torun but, by Tagge's request, Cylo and his surviving cyborgs were sent to accompany Vader as advisors and support during the campaign.
Tagge's trust in Cylo and his cyborgs would prove to be his undoing. Thanks to him, Voidgazer was able to aid Cylo in taking control of the Executor and subdued the grand general and the rest of the bridge crew with a nerve gas. After Vader killed the cyborgs and all the remaining clones of Cylo, Tagge was left with the blame for the attempted coup. For his failures and lack of judgement, Tagge was demoted by the Emperor and placed under Vader's command. Disgraced but desperate to survive, he insisted that, despite the disasters that had happened under his command, everything had worked to the Empire's advantage. As Tagge attempted to convince Vader of his continued usefulness, the Sith Lord cut him off by using the Force to strangle him to death while being watched by Tagge's fellow Admiral Kendal Ozzel, who was very happy to not be in Tagge's position.
In 3 ABY, Ozzel held admiralty over the Executor under Vader and brought its accompanying fleet, Death Squadron, close to the planet Hoth in an attempt to surprise the rebel forces on the surface. Ozzel's decision, however, alerted the rebels to the incoming attack and thus resulted in them raising a planetary energy shield. Enraged, Vader began to Force choke Ozzel, much like how he had killed Tagge. Ozzel thought about Tagge's execution during his strangulation but assumed Vader was simply teaching him a lesson, only to realize as the choke continued that Vader intended to kill him.
According to Resistance Admiral Ushos O. Statura, some of the tactics employed by Tagge were taught at naval academies by 34 ABY. In the same year, Gial Ackbar acknowledged that Tagge was a "canny adversary."

Cassio Tagge, a man with fair skin, possessed brown eyes and hair. He was tall and heavily built, with a wide face and a cleft chin. By the Empire's sixth year, he sported long, flaring sideburns, which he retained more than fourteen years later.
Tagge was regarded as a persistent yet uninspired leader as Chief of the Imperial Army, frequently clashing with Imperial Navy rivals such as Dodd Rancit and Conan Antonio Motti on strategic matters. Nevertheless, he was a methodical person who enjoyed creating and analyzing models of Imperial Fleet activity. Tagge was among the few high-ranking Imperials who considered the fledgling rebellion a serious threat to the Empire, a view that colleagues like Motti considered "distressingly myopic" regarding the Rebel Alliance. His concerns would be proven correct after the Death Star's destruction.
Before the meeting where Vader choked Motti, Tagge believed the Death Star was the Imperial arsenal's greatest weapon, but he began to change his mind after witnessing Vader's power firsthand. Following the Death Star's destruction and his subsequent promotion to Grand General, Tagge became overconfident with the power and authority he gained. Despite witnessing Vader's power firsthand, he was condescending towards the Dark Lord, whom he saw as a weapon, and arrogantly believed he could wield Vader as his personal weapon. Despite his successful analytics, his antagonism with Vader, combined with his poor judgment in the Cylo affair, led to his demotion and immediate death.
Cassio Tagge wore the standard gray or green uniform consisting of an Imperial officer's tunic, flared/normal pants, a black utility belt, and black durasteel-toed boots. As a General, he wore a single row rank insignia plaque of 6 red squares and 3 code cylinders (2 in the left and 1 in the right pocket). When promoted to Grand General, he wore a double row rank insignia plaque of (right to left) 3 blue, followed by 2 gold squares, on top of 3 blue, followed by 3 red squares, plus 3 code cylinders (2 in the left and 1 in the right pocket), or none.
Don Henderson portrayed General Tagge in the 1977 film Star Wars: Episode IV A New Hope, the first film in the Star Wars original trilogy.
In Star Wars Legends, Tagge was depicted as dying when the Death Star exploded. When Kieron Gillen was writing the Star Wars: Darth Vader series for Marvel Comics and needed a military opponent for Vader, the Lucasfilm Story Group reviewed the film to see which generals were present on the Death Star at the end. Pablo Hidalgo realized Tagge disappears from the film halfway through, unlike Tarkin and Motti, and does not die onscreen. His role in the comic is also a reference to the Legends character Ulric Tagge, who was intended to be this Tagge before it was retconned due to inconsistent continuity between Star Wars products. Ulric would later be canonized in the 2020 comic book Doctor Aphra (2020) 5, however. Leland Chee, keeper of the Holocron continuity database, came up with giving Tagge the title of Grand General.
Tagge, along with Admiral Conan Antonio Motti and General Trech Molock, was scheduled to appear during an imperial summit on Eriadu in "The Summit," the fifteenth episode of the second season of the Disney+ animated television series Star Wars: The Bad Batch. However, it was eventually decided that none of these officers would have been high-ranking enough this early in the Empire's existence.

"The Rise of the Rebellion and the Battle of Yavin" contains inconsistencies regarding Tagge's military rank. In the French edition of the encyclopedia book on page 21, Tagge is identified as a Major General. Later in the same book on page 62, Tagge is identified as a Grand General, despite only being promoted to that rank following the events covered by the encyclopedia. In the American edition of the book, Tagge is established as a Grand General rather than Major General, and later stated to hold the rank of High General. Due to inconsistencies presented by the different editions of the encyclopedia, this article assumes Tagge's standard rank of General as correct, per previously established sources.