Heirs of Bone and Sea by Kay Adams

Dive into the grand adventure of two young royals seeking to end the war between their two kingdoms in what Kirkus calls, "A Sapphic fantasy romance series-opener brimming with blood and longing."
Climb the tower. Kill the princess.

Evhen, princess-no, queen-of Vodaeard, is on a revenge mission. After witnessing her parents' brutal murder by the king of Marama and the horror of his undead army, she's vowed to kill his daughter. It'll be poetic justice and also take away his supernatural edge in the war. But when she realizes the princess might be an ignorant pawn, she changes course and hides her royal identity-after all, she can't trust an enemy, no matter how beautiful she is.

Stay alive. Break the curse.

Princess Kalei of Marama is moon-blessed, allowing her to resurrect her kingdom's loyal subjects. But when she's attacked in her safe lighthouse by a fiery pirate, her worldview is shattered once she learns what her power is really being used for. Determined to prove her innocence and willingness to stop her father, she has no choice but to trust her would-be killer to safely deliver her to the Vodaeardean princess. But who can she trust in when it seems Captain Evhen is not the only one who wants her dead?