Clan

You may be looking for the player groups known as clans. A clan is a group of people united by actual or perceived kinship and descent. Even if actual lineage patterns are unknown, clan members may nonetheless recognize a founding member or apical ancestor. The kinship-based bonds may be merely symbolical in nature, whereby the clan shares a "stipulated" common ancestor that is a symbol of the clan's unity. Humans, Forerunners, Sangheili, Kig-Yar, and Jiralhanae live or have lived in a clan-based lifestyle at some point in their history.

Sangheili
Sangheili clans are similar to those of the Highland Scots, in the sense that those within a clan operate as a single family, whose family name originates from their founder (the Sangheili Vadam clan was presumably founded by a Sangheili by the name of Vadam). Clans appear to be settled (Non-Nomadic) in territories (ie. the State of Vadam). Like the Scottish clans, they are run by a tribal chief (a Kaidon), who is supported by a council of Elders.

Kig-Yar
Kig-Yar clans ruled their homeworld before they were incorporated into the Covenant. These clans would often compete for resources and raid each other's cities or hold inter-clan competitions in major population centers. Even after the Covenant's dissolution, clans still remained a factor of Kig-Yar society, though they no longer hold as much influence as they once did. Kig-Yar clans often work in unity, unless one clan has grievances with another.

Jiralhanae
Jiralhanae clans are more primitive, though still share similarities to the Sangheili clans. Jiralhanae clans are typically referred to as packs, with several different pack organizations. They appear to be Nomadic and lack Elders, making the leader (a chieftain) their sole commander. New Chieftains can be recognized quickly, when a clan-member kills his chieftain in honorable combat.

Forerunner
Forerunner Builder families were organized into clans. These clans formed alliances with each other and held tributes and records of their ancestors.