The 82nd Last Hope was a division-sized unit that served under the Covenant in the Demon Spawn War. The unit was comprised entirely of tritons, and before Asmodeus became the Supreme Covenant Commander, they had served under him for more than a century. They guarded the sea lanes while he carried out land operations or in attacks against aquatic demons. Asmodeus considered them his most loyal and obedient unit.
"How is it that he turned all those triton legionnaires into devil-kin?" - Sathel
"It was part of a loyalty pact made by the tritons of the 82nd Last Hope, a soul-binding pact performed with primordial rites dating back to the Dawn Era. It would seem our former supreme commander was dabbling in forbidden primordial magic on the side." - Athena
- conversation between Sathel and Athena, from a Plaque of Aphalur - "Legionnaires Oath"
When Asmodeus became a Fallen Angel (9414 GE), thousands went with them. Entire units left the Covenant, picking loyalty to their former commander over Covenant ideals. The 82nd was one of those that followed Asmodeus to what was then better known as Ellubôz, or the Forge Worlds. With no objections, at least none openly, Asmodeus became the System Overlord of these worlds. With this title came a great power, the power of transformation. This was used on the tritons of the 82nd Last Hope, turning them into a sinister version of their namesakes, becoming the first members of the Sahuagin race.
In 9495 GE, wanting to expand his influence in the Mortal Systems, Asmodeus's sent his sahuagin back to Bal-Kriav. It took many centuries, but eventually they came around to seriously worshiping their former commander, helping him become a Higher Power on 9 War March 721 HE.