The Altean Colony were a group of Alteans that had originally survived the destruction of their home planet of Altea at the hands of the Galra Empire. During his banishment, Lotor gathered these Alteans and established the Altean colony in the Quantum Abyss. Originally meant as a safe haven for the Alteans, Lotor soon turn to using many of its inhabitants as a source of pure quintessence for his experiments. Because they weren't aware of what Lotor was secretly doing to a select few of them on the "second colony", Honerva uses the high, respected view they have for her son as a means to recruit them to her side.
The Altean colony was originally established as a place where Alteans could escape prosecution from Zarkon and his empire. It was built on a base on a remote planet at the end of the Quantum Abyss so that all but the most skilled of pilots could not reach the colony. Lotor was said to have worked alongside the Alteans in developing the colony, and over time the Altean people had begun to see him as a god whom they erected a statue for and worshiped.
Eventually, Lotor began to test Alteans for quintessential might, claiming these Alteans will go establish a different colony. There was to be no communication between this colony and the apparent second colony. In reality, Lotor had taken these colonists to a laboratory base on the moon of the planet where the original colony was from, and Lotor had used these Alteans to harvest their quintessence. This was not found out until Bandor, one of these harvested Alteans, managed to escape and warn his sister Romelle. Romelle will later go on to inform Keith, Krolia and later the rest of Team Voltron.
After Lotor is killed by Voltron, Honerva, who had learned of the colony by spying through the clone Shiro who had listened to Romelle tell her story, goes to the colony to recruit the colonists to avenge Lotor. She takes them to Oriande and makes them her soldiers for her new komar mechas, destroying Oriande in the process. After Haggar gives up her life to restore the realities she has destroyed, the Altean colonists become the citizens of the new Altea.