Reygan Mart didn’t have luck. His mate became the one who is absolutely not meant for him—the one who irritates him just by her presence, who doesn’t behave the way a pair should, angering even his dragon. But mates aren’t chosen. No matter how you try to delay the moment the mark appears on the dragoness’s body—you can’t avoid it… Unless you’re a dragon of darkness. And you just happen to meet an isekai heroine ready to become a fake fiancée.