Thad is the ranger, Nori is the mage, but Nori is a revenant with a dual mission
mission one: to bring down James Elliott, because he burned down the Doorman estate to acquire the sapphire serpent (he did not order this, he did it himself because he HATED the Doorman family, specifically Khan.)
mission 2: aid her daughter in destroying the Absolute Solver
i also think that Nori will only appear AFTER Uzi unlocks the vault
idk when Thad should appear, but his connection to the party will be that he is a childhood friend of Uzi's.
also the reason Lord Elliott hated Khan is that they once competed for the affection of Nori, and Nori chose Khan. at first James was happy for his best friend, but then fiendish and/or eldritch influences twisted his mind to make him jealous and hateful. this influence started shortly after Uzi was born. the estate was burned the night of Uzi's 16th birthday, after a gala was held in her honor. many believed it was the work of a devil, especially since the flames contained the heat of Avernus, first of the Nine Hells. Uzi was never found in the rubble, so much effort was put into finding her, but no trace of her was found.
until now...
an epic origin story in my opinion that i might use for D&D