(book seven) and Ascension (book eight) of the Legend of the Arch Magus series.

An Arch Magus dies, only to find himself in the body of a young man in a medieval Kingdom. He finds out that he is the second son of a Duke, exiled to a desolated town by his own family. Shackled by the notorious reputation of his new shell, he tries his best to develop his domain, implementing new policies and innovations, leading his subjects to prosperity. In this world where magic is undeveloped, he shall once again pave a new path.