Pong Krell was a Besalisk male Jedi Master who held the rank of Jedi General within the Grand Army of the Republic during the Clone Wars. However, as the Battle of Umbara approached, occurring around a specific time, Krell experienced a force vision of the impending doom of both the Jedi Order and the Galactic Republic. Consequently, he secretly embraced the dark side of the Force, aligned himself with the Sith, and sought to join the emerging New Order. Krell, wielding two double-bladed lightsabers, was a formidable and aggressive combatant, particularly adept at fighting in close quarters. Despite having the highest number of clone trooper deaths under his command, his impressive war record included numerous significant victories, establishing Krell as one of the most accomplished generals in the Republic Military.
During the Umbara campaign, Krell temporarily took over as commanding officer of the 501st Legion, replacing Jedi General Anakin Skywalker. He intentionally worked to sabotage the Republic's attempts to occupy the Separatist planet, believing that his actions would secure him an apprenticeship with Count Dooku. The legion launched a mutiny against Krell after he deceived them into engaging in combat with other clones. With the assistance of the 212th Attack Battalion, the 501st successfully captured Krell. Upon discovering his intentions through interrogation, Clone Captain Rex initially intended to execute Krell for treason, but ultimately trooper Dogma was the one who fatally shot the disgraced Jedi, resulting in Krell's death.

As a Force-sensitive Besalisk male, Pong Krell attained the esteemed position of Master within the Jedi Order by the time the Clone Wars erupted. When the Galactic Republic called upon the Jedi for their service, Krell answered the call, becoming a General in the newly established Grand Army of the Republic. Several weeks after the war's commencement, Krell attended a meeting at the Jedi Temple between the Jedi Order and members of the Galactic Senate. During this meeting, Krell displayed a disapproving expression but remained silent when Grand Master Yoda and Master Plo Koon advocated for treating the clone troopers under their command as individuals with unique identities.
On one occasion, Jedi Knight Iskat Akaris requested Krell to instruct her in Jar'Kai. However, due to his frequent absences from the Temple, it was impossible to arrange such training. Therefore, he advised her to consult Master Kelleran Beq.
Throughout the war, Krell amassed numerous victories despite the significant casualties suffered by the clones under his leadership. At some juncture, Krell succumbed to the allure of the dark side of the Force. Subsequently, he experienced a premonition foretelling the future: the Jedi were nearly extinct, the Republic was internally destroyed from the inside, and a New Order rose to take its place. This vision prompted Krell to betray both the Republic and the Jedi Order. While outwardly maintaining his Jedi persona, he secretly disavowed the Jedi path and became unofficially affiliated with the Sith. Acting as a double agent, he sabotaged the Republic's efforts and aspired to become the new apprentice of Sith Lord and Separatist leader Count Dooku, seeking a position of influence in the New Order. Although Supreme Chancellor Palpatine was aware of the high clone casualties and the questionable nature of Pong Krell, he was satisfied with allowing Krell to cause havoc among the clone troopers.

In 20 BBY, the Jedi High Council dispatched Krell, along with Jedi Generals Obi-Wan Kenobi, Saesee Tiin, and Anakin Skywalker, to retake Umbara from its Confederate-aligned Umbaran Militia. Krell subsequently provided air support to Skywalker's forces. Following this, Krell met with Skywalker and informed him that he was being summoned back to Coruscant at the joint request of Palpatine and the Jedi Council. Simultaneously, Krell was granted command of the 501st Legion.
Krell then led the 501st towards the outskirts of the capital. Disregarding the concerns of Captain Rex, whom Krell persistently addressed by his designation CT-7567 rather than his chosen name, Krell opted to attack the city by advancing along the main road instead of flanking the capital. Consequently, Rex and his troopers were compelled to retreat from the capital, much to Krell's displeasure. Krell and his forces then maintained their position against the militia and their Zenuas 33 Umbaran starfighters. Subsequently, Krell received a communication from Kenobi, who informed them that an airbase was providing resupplies to the capital. Krell and the 501st were assigned the task of capturing the airbase.

As the 501st approached the airbase's periphery, Krell directed Rex and the battalion to traverse a ravine to seize the airfield. Despite the objections of Rex and his troopers, they proceeded into the ravine. However, they encountered intense fire from the Militia's impeding assault tanks and mobile heavy cannons. Krell refused to permit Rex and the battalion to retreat or to provide them with reinforcements. Despite sustaining heavy casualties, the clones successfully captured the airbase. Krell then opposed the clones' proposal to utilize stolen enemy Umbaran ships to attack a Separatist supply ship. Instead, he commanded the troopers to march directly into the path of enemy missile fire. Rather than face certain death by obeying these orders, several troopers covertly utilized the stolen ships and successfully destroyed the supply ships, thereby aiding Kenobi's assault on the Umbaran capital city. Krell then had the soldiers who disobeyed his orders confined to the brig, intending to subject them to a court-martial followed by execution. Rex later visited Krell to implore him not to court-martial Jesse and Fives. Krell asserted that court-martialing them would be a waste of time, only to horrify Rex by ordering the immediate execution of Jesse and Fives.
The troopers refused to carry out the execution. Krell informed the clones that enemy soldiers had stolen Republic weapons and armor and ordered them into battle. During the engagement, the clones discovered that Krell had lied and had instructed the 212th and 501st to attack each other without the knowledge of either force. Rex realized that Krell had deliberately orchestrated the deaths of countless clone troopers and organized the surviving clones to apprehend Krell.

Under the leadership of Captain Rex, the combined forces of the 212th and 501st entered the command center and aimed their weapons at General Krell. Rex informed the traitorous Krell that he was being relieved of his command. Krell turned to face the captain and calmly stated that Rex was the one committing treason. Rex drew his pistols, ordered Krell to surrender, and demanded to know the reasons behind Krell's actions. Krell feigned ignorance before mocking the captain, expressing surprise that a clone was capable of discerning his scheme. As the clones approached, Krell used his four arms to unleash a Force push, knocking all of his assailants off their feet. Krell drew both of his lightsabers and expressed anger that the clones would dare attack a Jedi. The Jedi then began deflecting the incoming blaster fire while simultaneously cutting through the clones. He briefly paused his slaughter to tell Rex that he would not be undermined by creatures bred in a laboratory. Smashing through the window, Krell safely landed on the ground below the command tower, where he was confronted by even more clones. Krell proceeded to swiftly dispatch the clones surrounding him before fleeing into the Umbaran wilderness. As more and more clones fired at him, Krell used a Force push to stun them all, allowing him to escape the airbase.

The clones, led by Rex, pursued Krell into the jungle, where he was awaiting their arrival. The general began massacring isolated groups of soldiers who were searching for him, hoping to divide and conquer the clone forces. While slaughtering one group, Krell noticed Fives watching him from a distance. Krell made his way to the group and began taunting Rex from the shadows. He informed the captain that he should have listened to Fives from the beginning, as he had been using the clones all along. Krell then jumped down from the trees onto a batch of five clones, laughing as he revealed himself. Once again he began deflecting their blaster fire while killing the clones. Supremely confident, Krell put his weapons away and began fighting the clones barehanded, picking one clone up and breaking their back over his knee. Eventually, the clone trooper Tup called out to the general, calling him ugly and daring him to come for him next. Krell, not noticing the trap being laid down for him, ran at the clone with murderous intent. As he lunged at Tup, a native vixus grabbed Krell with its tentacles. Although Krell was able to free himself from the creature, he was caught off guard and stunned by Tup. With the general unconscious, the clones were able to cuff Krell and take him into custody.

After capturing him, the clones placed Krell in a holding cell in the airbase. When Rex, Tup, Jesse, and Fives entered the cell block, Krell snarled at them in discontent. Rex approached Krell's cell and demanded to know the general's reasoning for killing his own soldiers. Krell told Rex he had simply done so because the clones were inferior and he wanted to prove it. Rex expressed anger that a Jedi like Krell would do such a thing. Krell corrected Rex, telling the clone captain that he was no longer naïve enough to be a Jedi. He informed Rex and the gathered clones that he had foreseen the rise of a new power and the destruction of the Jedi Order. Krell boasted that he would rule as part of the governing body that would inevitably replace the Republic. Rex accused the general of serving the Separatist Alliance, only to be reassured by Krell that he served only himself, but that he would soon follow a new master, Count Dooku. Krell believed that once he escaped prison and pushed the Republic forces from Umbara, Dooku would reward him by making the general his new Sith apprentice.
Krell was interrupted by Dogma, the only clone who had remained loyal to him and had subsequently been imprisoned in the cell next to Krell. Dogma expressed his disappointment in the general, asking Krell how he could betray his loyalty and trust. Pong merely insulted Dogma, stating that he relied on blind loyalty like his to make his plans work. Rex told Krell that he would never escape and he would never rise to power. Krell noted that Rex would never learn, as he knew the Umbarans would soon retake the airbase and free him. Krell then began meditating and the clones proceeded to leave.

Sometime later, Rex, Jesse, and Fives returned and released Dogma from his cell. Rex told Krell to turn around and step towards the wall as he drew his pistol, intending to execute the traitorous general. Krell complied with Rex's commands and Jesse opened the door to Krell's cell. Rex ordered Krell to get on his knees. Initially, Krell simply taunted the captain until Rex reiterated the order, at which point the general laid down on his knees. The traitorous Jedi once again taunted Rex, asking the captain how power over him felt. Krell told Rex that he could sense his fear, wondering why the clone couldn't bring himself to kill him. Eventually, Rex lowered his weapon as he didn't have the resolve to execute his commanding officer. As Krell began to respond to Rex's weakness, he was shot in the back. Dogma had seized Fives' blaster and shot Krell dead. Dogma insisted he had to shoot Krell for his treasonous deeds. Afterwards, Dogma himself was taken into Republic custody for killing an officer, but as he was led away, Rex gave him a reassuring nod to let him know that he did the right thing.

In 19 BBY, the Jedi Barriss Offee secretly bombed the hangar of the Jedi Temple in protest of the war and the decline of the Jedi Order. While investigating the scene of the crime, Jedi Padawan Ahsoka Tano expressed her disbelief to her master Anakin Skywalker that any Jedi would go so far to protest the ongoing war. In response, Anakin reminded Ahsoka that some Jedi who initially protested the corruption in the Order later turned against the Jedi Order, mentioning both Count Dooku and General Krell as examples.
After Quinlan Vos' fall to the dark side of the Force while on a mission to assassinate Dooku, most of the Council supported the idea of executing Vos, with Mace Windu citing that Vos was a Jedi Master with unique skills and that even Krell's deception did less damage. Ultimately, however, Vos was spared at the insistence of Obi-Wan Kenobi.
Decades later, Krell was mentioned as having been a notable Besalisk in "Species From A to Z," a survival compendium sent out by Carson Teva during the New Republic Era.

Pong Krell, a Besalisk male Jedi Master, possessed an imposing stature, standing at 2.36 meters (7 feet, 9 inches) tall, characterized by black hair, yellow eyes, and brown skin.
Renowned as a successful general, Pong Krell exhibited unwavering confidence in his command style, displaying zero tolerance for failure or insubordination among the clones serving under him. As a battlefield commander, he secured numerous critical victories for the Republic, a consequence of his unwavering focus on achieving results, regardless of the cost. His sole concern lay in achieving results in battle, readily sacrificing his men for tactical advantages. Unlike many other Jedi, he did not perceive a moral obligation to safeguard his troops and was willing to allow them to perish for the sake of victory or progress. This particular ideology placed him at odds with Captain Rex, who considered it his primary duty to protect the men under his command.
Krell's unconventional yet effective tactics were well-known among the clones. When Krell temporarily relieved General Skywalker of duty and assumed command of the 501st, several of the men immediately recognized Krell's name as the general responsible for the highest casualty rates. Krell frequently asserted his authority over Rex and the other clones to ensure compliance with his contentious orders. He reacted with disdain when the clones attempted to improve his strategies, improvise, or exercise independent thought. He attributed many of his less effective tactics to poor execution, blaming the men for failing to follow orders or to execute a part of his plan to his liking.
Krell possessed an unusual degree of callousness and arrogance by Jedi standards, reacting poorly to constructive criticism. He held clones in particular contempt, considering them little more than droids and equally expendable. Upon receiving a vision of the war's outcome, Krell prioritized his own survival, exhibiting no hesitation in betraying all of his allies to join the Sith. After his true allegiance was exposed by the men under his command, Krell reveled in slaughtering them in a fit of dark side-fueled madness, taunting them throughout. Like most adult Besalisks, his upper arms were dominant over the lower pair.

Pong Krell was a formidable Force user. His unique Besalisk anatomy enabled him to simultaneously wield two double-bladed lightsabers. Krell's lightsabers were distinctive in that they could fold in the middle, facilitating their portability. He wielded his lightsabers with lethal precision, spinning them like buzz saws to devastating effect, and he was capable of killing many clone troopers with ease. He could also deflect an innumerable amount of blaster bolts with similar ease.

Krell also possessed exceptional Force abilities, demonstrated when he utilized all four arms to unleash a Force push upon the clones attempting to apprehend him, sending them flying in all directions. Krell could also leap to extraordinary heights using Force jump, as evidenced when he employed this ability to dispatch two banshees and when he escaped the tower of the Umbaran airbase. In addition to mocking the clone troopers, he also exploited this ability to confuse them by making his voice reverberate in every direction. Furthermore, he could sense emotions through the Force, such as Captain Rex's fear and uncertainty. Krell also possessed the ability to foresee future events. This ability was pivotal in his conversion to the dark side, as he foresaw the near destruction of the Jedi, the fall of the Republic, and the rise of an Empire.
Although undermined by his own overconfidence and the ingenuity of trooper Tup, Krell easily massacred scores of clones, combining deadly lightsaber techniques with potent Force abilities. He was highly skilled in unarmed combat, which he displayed while fighting clones with his bare hands, using his considerable strength to pick up adversaries and throw them, at one point even breaking a trooper's spine over his leg. Despite his size, Krell proved himself to be a nimble and agile fighter as well, dodging and evading attacks.
Pong Krell made his debut in the Star Wars: The Clone Wars Season Four episode "Darkness on Umbara" and continued to appear throughout the show's Battle of Umbara arc. Prior to the premiere of Darkness on Umbara on October 28, 2011, Krell was first pictured and referenced in promotional material for The Clone Wars: Season Four; he was first pictured within the season's WonderCon preview and later teased by last name at Comic Con 2011, where "General Krell" was introduced as an unconventional, but still powerful, Besalisk Jedi who would make the clones question themselves in differing ways. His first name of "Pong" was later provided by the Launch Pad department of Star Wars Insider 129 on October 25, 2011. The official Star Wars UK Twitter account used Krell to promote Disney+ by introducing him as someone who might be "worse" than Darth Sidious.