I'm a Noble on the Brink of Ruin, So I Might as Well Try Mastering Magic (Manga): Volume 3

At the behest of the first princess, Liam takes on a new challenge: establishing his own country in the promised land of legend! What starts out as a spontaneous endeavor slowly but surely takes shape as more monsters flock to the abundant terrain. Although they get off to a rocky start, a nation to call home is no longer a distant dream thanks to the monsters' efforts, Liam's growing magic prowess, and a little bit of help from the ancient dragon now dwelling within Liam. But their hard work draws in more than just friendly faces. Confronted with the dual threats of invading human nations and an overwhelming force of hostile monsters, Liam and his allies must use all the power at their disposal to protect their new homeland!