Alpha Tribe

Alpha Tribes are a larger grouping of Jiralhanae, likely more than a Master-Pack, and seem to be the governing body of the Jiralhanae as a people.

History
Before the Brutes' integration in the Covenant, probably no Alpha tribes were in existence on their governing body, resulting the leadership to be fragmented, explaining the Master Pack's predominance during those times, which, ultimately, caused the civil wars that devastated Doisac.

The Alpha leadership was lured to Joyous Exultation under pretense of truce negotiations - actually a Sangheili ambush to eradicate the Jiralhanae leadership. The planet was devastated by a UNSC NOVA Bomb before the ambush could be sprung, and whether the Alphas survived, or even arrived, for that matter, is unknown.