The Fire of Purification was a military organization lead by Sendak, after Zarkon fell and Lotor ascended the throne of the Galra Empire. Its purpose was to "cleanse" the empire of what its members deemed unworthy, including half-galra. It's mainly made up of galra who did not side with Lotor after his ascension to the throne. Their most notable attack was the Raid on Earth when Voltron was caught in the three year time skip after the events of "Defender of all Universes."
After Lotor ascended to the Galra throne, Sendak formed the Fire of Purification as an opposition to his ruler ship. The group first made their appearance in "Omega Shield" where Sendak and his fleet appeared at the Omega Shield base, where he announces his disgust at Commander Bogh's loyalty to Lotor. The group then destroys the Omega shield that protects the base, with the intention that anyone that follows Lotor is not worthy of living.
During the three years Voltron lost after the destruction of the Castle of Lions, the Fire of Purification set out to conquer Earth, the home planet of the majority of the current paladins of Voltron. They had initially come to claim the Voltron Lions from Earth, where it was believed they were being hidden, but when it was revealed that the Lions were not present, the invasion turned to full scale colonization. The Fire of Purification set out to destroy all of the major cities on the planet, wiping out the majority of nations present, leaving only the Galaxy Garrison, which was protected by particle barrier technology. During the time skip, construction of six Zaiforge Canons began underway using the citizens of Earth as laborers, as Sendak and his forces waited for the inevitable return of Voltron.
When Voltron returned, the Fire of Purification bargained with Admiral Sanda to turn in the Lions for the end of the Invasion. This turn out to be a lie, as they continued their raid despite the request of Sanda. They captured the paladins of Voltron and locked them up, though this proved to be ineffective as the paladins could fly the lions without residing in the cockpit personally. Meanwhile, a fight between the Fire of Purification's fleet and the newly launched IGF-Atlas ensued where the Fire of Purification's fleet took heavy fire. During such battle Shiro infiltrated Sendak's main ship, which led to a fight between Sendak and Shiro, that ultimately lead to the crashing of Sendak's main ship onto Earth as Voltron had destroyed the ship. The Fire of Purification was presumably disbanded once Sendak was killed by Keith.
- Admiral Sanda (formerly)