After First Lantern suffered a mental split from overwhelming emotions and attacked the Guardians of the Universe, they knew things had gone wrong—beyond their control.
To prevent Volthoom from causing even greater harm, the Guardians of the Universe destroyed his Travel Lantern and trapped him in this universe.
When Volthoom discovered that his Travel Lantern had been destroyed and that he could no longer leave this universe, he flew into a rage and massacred the Guardians of the Universe, slaughtering countless of them and nearly driving their race to extinction.
Later, a Guardian of the Universe named Lani used the destroyed Travel Lantern and the green of willpower from the Emotional Spectrum to forge seven Green Lantern Rings, creating seven "Original Green Lanterns." Together with the entire civilization of the Guardians of the Universe, they defeated Volthoom, seized the First Lantern Ring, removed the Great Heart from Volthoom's chest, and imprisoned him in the "Dark Chamber."
The Guardians of the Universe erased Volthoom from history and took turns guarding him, ensuring that he could not escape his imprisonment.
As they gazed at the sealed Volthoom, the Guardians of the Universe felt deeply conflicted.
If they had been more careful back then, if they had not been so eager to implant the Great Heart into Volthoom's chest, perhaps none of this would have happened. At the very least, Volthoom would not have suffered a mental split that left the Guardians of the Universe with devastating casualties and nearly wiped them out.
And Volthoom could have returned to his own universe and saved his homeland and mother.
What had led to everything now was partly the Guardians of the Universe's negligence and lack of foresight, and partly Volthoom's haste and confidence in the Emotional Spectrum.
"Alas..." The Guardians of the Universe sighed