Throughout his life, Haruyoshi has aspired to be the most powerful onmiouji, not to mention that the rest of the inhabitants not only fear him, but despise him for being arrogant.
Fear can turn into hate, and because of that, one day he is betrayed, and whoever was his best student is sent to assassinate him.
Before dying, Haruyoshi partly understands why his actions ended up costing him his life, and swears that in his next reincarnation he will change his way of being.
Thus, the most powerful of the onmiouji begins a new life as Seika, who is told that he is the bastard son of a nobleman from the renowned Lamprogue family.
Over the years, Seika understands the difference between him and his older brothers. However, for him it does not matter, since he aspires to spend his days without attracting the attention of others.
When his father tests him to measure his affinity with known types of magic, Seika shows no sign of possessing powers; however, in reality, he still has the same strength and dexterity that he possessed in his previous life.
Over the years, his confrontation with one of his brothers becomes more evident every day, to a point, when Seika decides to put a stop to it and makes a fool of him in front of the rest of the family.
At that moment, Seika decides to ask his father to allow her to study magic, and even aspire to attend the academy to finish his training.
His father offers to start his education, but does not guarantee anything else in the future. Meanwhile, Seika finds out that Aifa, a slave who serves the family, has magical powers and decides to start teaching her how to use them.
Seika knows that in the future he will face challenges, and this time he does not intend to prove that he is the strongest, but that he is surrounded by equally powerful companions.
Years later, an immense creature appears and enters the family property, Seika’s brothers do not know what to do, and while one of them flees, Seika decides to face the monster.
With great skill, Seika demonstrates some of his powers and makes evident that he deserves a chance to attend the magic academy and not be sent to serve in the army.
Finally, his effort is appreciated by his father, who recognizes his son’s strange powers, and decides that it is safer for everyone if he is in a controlled environment like the academy, and not one where he could lose control and cause a disaster.
Seika is accompanied by Aifa, and when they take the entrance exam they meet Amyu, the daughter of a couple of adventurers, with a conflicting personality and supernatural powers, which make one think that she is the reincarnation of a legendary hero.
(最強陰陽師の異世界転生記)