The Battle of Mygeeto stands as one of the most protracted engagements of the Clone Wars, raging for a full two years after its commencement in 21 BBY. By 19 BBY, it had become integrated into the Galactic Republic's broader Outer Rim Sieges, aimed at securing the various planets within the expansive Outer Rim Territories.

The initial clashes on Mygeeto occurred in 21 BBY. During this time, the Galactic Marines executed a diversionary tactic for Walon Vau and Delta Squad, facilitating their retrieval of funds from the Vau family's underground vault on Mygeeto. This conflict persisted for a duration of two years, culminating when Supreme Chancellor Palpatine designated Mygeeto as part of a "Triad of Evil," a group of three planets that represented significant Separatist strongholds. Alongside Felucia and Saleucami, Mygeeto was specifically targeted as a crucial objective, with its capture expected to contribute significantly to ending the overall war.
The Republic deployed its military forces to the Mygeeto system, initiating an invasion of the planet. The Separatist blockade, which was relatively weak, was swiftly overcome, allowing the Republic to land ground troops on the planet's surface. As a result, the intensity of the battle escalated considerably. Mygeeto held significant importance as a major asset of the InterGalactic Banking Clan. The battle involved two primary Republic military units, with the Galactic Marines bearing the brunt of the intense fighting. They engaged the Separatist Droid Army in prolonged urban warfare amidst the advanced, towering structures of a major Mygeetan city. Additionally, elements of the 501st Legion also participated in the conflict as a second unit of the Grand Army. This unit was assigned a special mission directly from the Chancellor himself.
According to Mundi, the 501st were sent to Mygeeto with the stated objective of destroying an energy collector that supplied power to Separatist installations in the vicinity. However, the mission's actual purpose was to seize the Separatist power generator and secure the ancient Mygeetan crystal that powered it. The Chancellor needed the crystal, an experimental power source, for a highly classified laser-stream project referred to as "Hammertong."
Following the Republic's landing, the Galactic Marines initiated heavy bombardments of the Mygeetan terrain, employing torpedoes and incendiary attacks. The 501st were deployed to the southern sector of a small city. Only one gunship was able to land due to the presence of dual particle cannon turrets. Other gunships provided support from the air. An AT-RT was deployed, and the 501st launched an assault on the southernmost bridge. The troopers successfully captured the bridge and seized the Confederacy's forward command post. Subsequently, the two particle cannon turrets were destroyed, enabling General Mundi to land.
However, the situation became more complex when one of Ki-Adi-Mundi's fellow Jedi, Rivi-Anu, was shot in the arm and lost her lightsaber while attempting to secure the west flank. Furthermore, one of the Republic's Venator-class Star Destroyers was shot down over Mygeeto and was heading towards the battlefield, endangering several Republic units. Anu chose to use the Force to hold off the doomed Star Destroyer, giving Mundi and the other Republic forces enough time to evacuate the area. She died in the process. Mundi and Eon later contemplated her sacrifice.
Mundi destroyed two shield barricades to facilitate the advance of the 501st troopers. An outpost was captured, and more troopers were landed. The Separatists put up strong resistance, using AAT tanks. Additional AA guns were positioned at the north end of the central platform. The 501st, led by General Mundi, pushed the Confederacy battle droids' line across the northern bridge to the building that housed the energy collector. Ki-Adi-Mundi disabled shield barricades that protected the building's entrances. Destroyer droids inside the compound proved to be a minor obstacle, and the energy collector core was destroyed. After Mundi had been extracted, the 501st retrieved the crystal samples. The troopers fought through a Separatist counterattack to reach the southern platform and extracted the crystals via gunship.
The battle continued for the Galactic Marines. As the Republic launched a concentrated effort to defeat the Separatists, the fighting spread to the cities of Mygeeto. Ki-Adi-Mundi skillfully used his lightsaber to deflect enemy fire while leading a force of Marines supported by UT-AT assault vehicles and other heavy walkers. Tri-droids provided heavy fire for the Separatist army during the fighting and destroyed several UT-ATs.
The battle intensified on a series of large bridges that spanned a large chasm, connecting several city districts. The clones continued to advance across the bridges. It was on these bridges that Ki-Adi-Mundi would fight his last battle.

When General Grievous was killed by Obi-Wan Kenobi on Utapau, and Supreme Chancellor Palpatine announced the Declaration of a New Order, General Mundi was still in command of Republic forces on Mygeeto. While General Mundi was rallying his troops on a bridge that crossed a chasm between two city blocks, and as enemy droids were destroying several UT-ATs, Commander Bacara received a communication through a secure, holographic comlink that was frequency-locked to a channel reserved for the Commander-in-Chief. The hologram showed a hooded and badly disfigured Darth Sidious, Dark Lord of the Sith, ordering him to execute Order 66.
Bacara obeyed, and moments later, on his order, the clones closest to General Mundi abruptly stopped fighting. Confused, Ki-Adi-Mundi turned around and was shot by clone fire. The surprised Jedi Master managed to kill three Marines by deflecting their fire, but the sheer number of blaster bolts overwhelmed him, resulting in his death.
Following Mundi's death, the newly formed Galactic Empire proceeded to conquer the planet, claiming it for Palpatine, who had now assumed the title of Emperor. The Imperial military maintained strict control during the turbulent period following the Clone Wars. They extensively strip-mined the planet for a mineral called durasteel, which was used in the construction of starship hulls.
In the story To the Vanishing Point, the battle in which Rivi-Anu died was originally intended to take place on a different planet than Mygeeto. However, the authors of The Complete Star Wars Encyclopedia clarified in Rivi-Anu's entry that the events of the story actually occurred on Mygeeto.