Overlord Vol 6 (light novel): The Men of the Kingdom Part II

The underground organization known as Eight Fingers and their strongest fighters, the Six Arms, make their move. Blue Rose, the adamantite-rank group of adventurers led by Lakyus, prepares to take them on. As the knights head to the front lines to protect the princess, the mysterious demon Jaldabaoth lurks in the chaos of this critical battle, and the capital descends into an uproar swathed in crimson flames.