The Bone Court's Cursed Bride, livre ebook

A dead man lies at the base of the Bone Gate, one arm thrown wide, frost settling on his open eyes. His coat is the deep violet of Shadow Court livery. The dagger left in the wound is carved bone with the Duvall crest on the pommel — standard Bone Court armory stock.
Rosalind is not convinced by either of those things. There is silver residue along the edges of the cut, and it is Inquisition blades that are treated with a silver alloy. *"The question is which version serves whoever put him here."*
Her mother has been dead six days. The wasting sickness that took the Duchess took her grandmother and her grandmother's grandmother before her, and the Bone Court's necromancers could do nothing but spend three servants' lives failing. Rosalind is heir by blood and by training. The succession is not official until the Council votes, and her cousin Marguerite has been working the Council for years.
Then Lord Sebastien Moreau asks to meet on neutral ground, in the Veilwood, where no court's magic works properly and nobody can be listened to.
What he wants is an alliance. A binding marriage between the two courts, merging territories against the Inquisition — and, more usefully, opening the prison where they are holding his brother and hers.
Sebastien has his own clock running. The shadow-curse killed his father blind and raving, clawing at his own eyes, and it has already started on the son: black creeping past the quick of his fingernails, spreading inward.
Rosalind's trouble is closer to home. Somebody told the ambushers where to stand in the Veilwood. Somebody has been talking to the Inquisition. And the person she trusted with her childhood secrets is the one who used to line up her dolls and perform the funeral rites over them.
*"Trust is a wound."*
What follows runs through catacombs, a cistern, an abbey drain, a prison and a forest on fire, and neither of them comes out of it with what they started with. Sebastien loses more than his sight. Rosalind loses the last thing holding her together. And the marriage everyone assumed was a transaction turns into the only thing either of them asks for on their own account.
This is a gothic court romantasy about two heirs from rival courts, a corpse planted to start a war, and an alliance that keeps outgrowing its terms. The romance is closed-door.