The Human-Covenant war had taken a turn for the Covenant after the death of the Prophet of Regret, and the replacement of the Sangheili for the Brutes. Since then, a portion of the Sangheili have broken away from the Covenant. Currently, the Arbiter had just made it out of a complex and unintentionally met up with Rtas' Vadum, who is in a Wraith.

Rtas 'Vadum: Upon opening up the hatch and looking out to Arbiter, he seemed surprised to see him here. By the rings! Arbiter! The Councilors! Are they-

Arbiter: Murdered. By the Brutes.

Rtas 'Vadum: Vile, disloyal beasts! The Prophets were fools to trust them.

Arbiter: No matter, we must press forward. The Prophets have betrayed us. Many more will join our cause soon, that I am sure of. Until then, what is our plan?