Horus Rebellion

“	The Pirate attacks must have the old man nervous. Looks like he's getting ready for full-scale invasion. No joke. Last time this many fighters were scrambled was during the Horus Rebellion. That was some nasty business. I have a feeling this will be worse.	„
—Two Male Fleet Troopers on the G.F.S. Olympus

The Horus Rebellion was an intense skirmish mentioned by G.F.S. Olympus crewmen in Metroid Prime 3: Corruption. At the beginning of the game, one male Fleet trooper can be overheard telling another that he is reminded of the rebellion by the Galactic Federation's sudden militarization in the face of the Phazon crisis and collapse of the Aurora Unit network. The troopers' conversation implies that it was a difficult battle that required the deployment of at least as many Stiletto fighters as the Pirate attack during Corruption, but nothing else is known about the Federation's military response. One of the troopers also speculates that the Pirates' actions and Dane's planned response might be even worse than during the Horus Rebellion. It is impossible to extract any further information from the troopers – if Samus attempts to speak to them directly, they will dismiss her and claim that they are too busy performing their duties, as do all other troopers onboard the Olympus.

Unused Logbook entries mention that a battle (presumably the Horus Rebellion) took place on a planet called Horus IV, at an undetermined date. It is not known why or how the rebellion occurred, or for that matter what role the Federation played. The eventual outcome of the Horus Rebellion is also unknown, although it is implied that the Federation suffered heavy casualties in the fighting as the G.F.S. Valhalla's entire bridge crew was slain forcing Aurora Unit 313 to take command.

Trivia

• In Egyptian mythology, Horus was the son of Osiris and Isis. He was god of the sky, with the sun as his right eye and the moon as his left, and was represented as a falcon-headed man. He was a warrior and a hunter, and held a long time rivalry with Set, the god of the desert and the murderer of Osiris, which culminated with many battles to gain the rightful throne of Egypt.
• The rebellion is a possible reference to Warhammer 40 000, a tabletop game produced by Games Workshop. In this universe, a rebellion known as the "Horus Heresy" took place led by Warmaster Horus, son of the Emperor of Mankind, who was corrupted by the Chaos Gods (similar to Dark Samus' corruption of the Space Pirates). This created a large schism in the Imperium of Man. Interestingly one of the early daemons which appeared within the series was called Samus.