Like many of the Duergar at Grymforge, Brithvar holds no real loyalty towards the Absolute and resents Nere for withholding his money. While initially suspicious of the party, as his ability as a Duergar to detect Illithid presences makes him believe them to be a True Soul, he can be convinced otherwise and talked into leading a mutiny against Nere through advancing the quest Blind the Absolute, causing roughly half the Duergar including his lieutenant Stone Guard Kur to fight against Nere alongside the party once the Drow is freed. Afterwards, he and the surviving Duergar will leave Grymforge after a Long Rest before any Absolute reinforcements can show up. He can be persuaded or intimidated into leaving the gnome slaves behind before he leaves, allowing them to head back to Baldur's Gate.