Robin's partnership with Frey is due to an association between her or one of her family members with Nadezha.
Soloviev and Nadezha are names of Slavic origin, so maybe this Commonality Connection runs deeper.Vance's family will die, contributing to his Break the Cutie.
Frey's mother is a political prisoner and his father seems to be out of the picture, and who knows what happened to Robin's family. Given that Frey's Missing Mom seems to be what caused him to be a part of the La Résistance and it would be reasonable to assume that Robin's Dark and Troubled Past is why she is too, it'd make sense that something equally bad would happen to Vance that would cause him to turn into a dark brooding hero that he'll soon be.