Oops, I Tamed the Commander Everyone Dreaded

On a sandy planet where humans are pushed to the very bottom, Lyra walks into the Obsidian Palace to take part in Commander Kael's mate test, hoping to pay off the gambling debts of Ethan, Kael's boyfriend. Instead, she discovers she is the only fated mate meant for Kael. Serena, a scheming heiress from a great house, soon plots to destroy her, while Ethan, once kind, has become hard-hearted toward her. Lyra must also deal with Kael's dying star core, and she is the only person he will obey.