As a Reincarnated Aristocrat, I'll Use My Appraisal Skill to Rise in the World Volume 7 (light novel‪)‬

Ars Louvent, former Japanese businessman turned young head of a noble house, has climbed the ranks of the aristocracy thanks to his unique ability: a skill called Appraisal. With it, he's gathered a whole host of capable retainers from all walks of life to aid and protect him! Under Ars's leadership, House Louvent has become a force mighty enough to single-handedly alter the course of wars. His growing power, however, did not go unnoticed by his foes, who dispatched an assassin and nearly succeeded in claiming Ars's life. Ars was left bedridden…but the fact that he was out of the action didn't mean that House Louvent's progress came to a standstill. Word has arrived that Shin Seimallo, the engineer Ars recruited in the imperial capital, has finally achieved his ultimate goal. The airship is complete, and thanks to it, the nature of warfare in Summerforth is about to be turned on its head!