The Horde is a race of one minded individuals with the sole purpose of expand and consume. They are one of the races taken by the Appa Ali Apsa insane Guardian when he created Mosaic World.
The Horde was created by Gerard Jones for his four part Mosaic story arc in Green Lantern, that was later continued in Mosaic. The Horde are never really given a real name but are just referred to as the horde of aliens.
Major Story Arc
Two human teenagers decide to explore their new world of Mosaic when they spot the Horde for the first time. The Horde kills them without provocation, but its due to their mentality of expand and consume, and the Horde believes they have done nothing wrong.
This act of violence angers the rest of the human’s trapped on Mosaic and they attack the Horde. John Stewart intervenes but due to the fact that the Horde uses yellow ray weapons, John needs to retreat and rethink. He comes up with a plan to make a temporary wall and this slows the Horde down.
The human keep attacking the Horde and when John shows up again the Horde is forced to retreat. When they do they leave one of their own behind. Rose Hardin and John take him back to John's home where he tends to the alien’s wounds.
The Horde and the humans continue to fight and this time John makes a more permanent wall between the humans and the Horde. Then due to the humans other actions, John makes a wall between all aliens on Mosaic. The Horde become quiet once the walls are up until Rose contacts them and explains the misunderstanding.
The Horde then communicate with John that they have seen the errors of their way and help him when his wall collapsed and chaos takes over. After John and some other Green Lanterns stop the infighting John asks the Horde to help with the rebuilding of Mosaic.