When the Pole Jester manifested the GLEENGI and the PeRBS, starting the universe, they were already complete opposites. The Perbs were the deities of all that is benevolent, and the Gleengi were the deities of all that is malevolent.
The Gleengi did not do so much as to think fondky of one another. In fact, they would sometimes fight one another to gain more respect, often leading to death. Eventually, one Gleengus-- John GLEENGUS, decided to get rid of all of the other Gleengi. Over the next year, John GLEENGUS would do nothing but kill other Gleengi.
Once there was only one other Gleengus left, John Gleengus felt changes occuring to his body. John Gleengus' skin turned deep purple, and he felt a sharp pain within himself. He charged at the second-to-last Gleengus, before stopping in his tracks and screaming. This was the moment Gleengus got his infamous soul-stealing screech. However, to souless beings such as deities, the scream would just dissolve them.