The Inner Sphere (abbreviated IS) is a common name to the area 450 - 550 light-years away from Earth, occupied by the Great Houses. It is one of the 2 factions that oppose each other in the Team Solaris Arena, Test of Strength and Terrain Control game modes.
The Inner Sphere makes up the region of space between Terra (Earth), and the periphery. There are several minor states and organizations that hold several star systems, but there's only 5 major empires, each ruled by one House:
- Federated Commonwelth (union of House Steiner and Davion at the time of Clan Invasion)
- House Steiner rules Lyran Commonwealth
- House Davion rules Federated Suns
- House Kurita rules Draconis Combine
- House Liao rules Capellan Confederation
- House Marik rules Free Worlds League
Once united under the Star League, it has fallen apart into successive wars against each other. These were called the Succession Wars, four in total. These wars put heavy tolls on society and technology, many of the factories were either destroyed or lost during the collapse of the Star League and the first Succession wars.