Queenslayer

In the fifth book of Sebastien de Castell's adventure fantasy series, Kellen Argos, a failed mage and notorious outlaw, finds himself facing execution for accidentally tarnishing the Daroman flag. Presented with a chance for freedom by the queen, he must outplay her in a high-stakes card game. However, the game quickly unveils a conspiracy against the monarchy, and Kellen soon realizes he is fighting not only for his own life but also for the future of the empire.