The Princess of Convenient Plot Devices, Vol. 5 (manga)

Princess Octavia finds the maruaders and the kidnapped Sil in the true Sky Chamber—but as she and her allies attempt to carry out their rescue, they are attacked by Sil himself! But Octavia notices that Sil isn’t acting like himself...Will she be able to snap her brother’s lover out of whatever affliction he’s under before Klifford is forced to cut him down?