Halo Alpha
Halo Alpha

Sigma Octanus IV, located in the Sigma Octanus star system in FLEETCOM Sector Three.[3] It is a remote colony planet with one natural satellite[1] and a population of nearly seventeen million citizens before the Battle of Sigma Octanus IV.[2]


The Forerunners[]

A meteor containing a Forerunner artifact crashed on the planet on 57,448 BCE, to be discovered by humanity approximately 60,000 years later and placed for display in the Côte d'Azur Museum of Natural History.[4]

Human-Covenant War[]

Main article: Battle of Sigma Octanus IV

In July of 2552, the battle began with the invasion of the crusading alien faction, the Covenant. One of the planet's major population centers, Côte d'Azur, was attacked by Covenant ground forces and the Spartan IIs were deployed to find out why the Covenant were so interested in the city. The museum of the city held a Forerunner artifact that the Covenant wanted and the Spartans were able to retrieve this artifact, more specifically a rock sample with rubies in it, and level Côte d'Azur and the Covenant presence within with a HAVOK Nuclear Warhead. Later on, it was discovered that the Forerunner artifact contained directions to Installation 04,[5] in the form of a star map reference. It was only noticed by Cortana after her attempts to translate it as a language failed.

The Covenant invasion of Sigma Octanus IV was actually a distraction to retrieve the Forerunner artifact in the museum in Côte d'Azur. This is most likely the reason why Sigma Octanus IV survived being glassed.[6] Annihilation was not limited to Côte d'Azur, as the other cities of Caracas, Huiren, Silma, and Enfield were also horribly affected. However, it has not been revealed if they were destroyed by the Covenant's invasion or they were preemptively destroyed by desperate UNSC forces.[7]

Physical Aspects[]


It features a warm, humid atmosphere that is perfect for growing warm weather crops, giving rise to the planet's many rice fields.[8] Much of the planet is a dense jungle and it appears that a meteor containing Forerunner artifacts crashed into the planet before Humanity's arrival.[4]


Known Residents[]