The Magician Who Rose From Failure: Volume 2 by Hitsuji Gamei

Drawing on knowledge gained from his dream of a second life in another world, Arcus created the aethometer: a device that measures the essence of all magic. Now, he is finally ready to present his revolutionary invention to his nation’s premier magicians and military leaders. With the circle of trust containing the device’s earthshaking implications cast wider, how will the aethometer move to change Arcus’ fate and the fate of the world itself?

Others within the gentry are keeping a close eye on Arcus after his decisive actions on the marquess’ estate. Whether they are friend or foe remains to be seen—but subtle machinations rarely remain so for long when Arcus is involved.