Ore, Akuyaku Kishi Danchou ni Tensei suru.

Justin is the commander of the Order of the Knights, who is arrogant, ruthless, and the object of fear of everyone. One day, he remembers that he used to be a college student who was completely swamped with taking care of his 7 little brothers. According to those memories, he's now in the world of a light novel! And what awaits him ahead is... a one-way route to ruin which is the result of his bad deeds?! Justin decides to change his ways in order to change the future, and he makes a vow to himself to properly discipline the members of the Knights' Order using his "big brother skills" that he cultivated in his previous life, but... Not only do the several "good deeds" that the Villainous Commander started does not only change things in the Order, but go on to cause huge changes in the whole country...?! (Source: Kadokawa, translated)