From Halopedia, the Halo wiki
Sangheili Mercenaries, or Elite Mercenaries, are the standard low ranking Sangheili mercenaries working for the Banished. While the Banished Sangheili are mercenaries in general, higher ranking individuals can hold titles such as Ultra, or Shipmaster as Let 'Volir did.
While many Sangheili continued to genocidally hunt down and slaughter the Jiralhanae, a few were persuaded by Atriox to work for the Banished, as he claimed to have no complicity with Tartarus and the other Jiralhanae who had betrayed and massacred their kind. As such, a small minority of Sangheili have joined the Banished as mercenaries, some of which used their earnings of military resources to fight out disputes with other Sangheili kin on their homeworlds. Joining the Banished was frowned upon in Sangheili culture, Let 'Volir's name was notably forever tarnished for working under a Jiralhanae.
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