As a Reincarnated Aristocrat, I'll Use My Appraisal Skill to Rise in the World Manga, Vol. 14

After becoming the Count of Canarre, Ars hires two exceptionally talented individuals to join the Louvent family Zaht, a highly skilled soldier and Musia, a shy girl who possesses hidden nagical abilities. As the new members of the family settle into their roles, Ars is shocked to hear the neighboring duchy of Seitz is marching on Canarre with an army of 80,000 soldiers! The surprise attack was clearly timed for after Ars's inauguration…but why?!