An older sister with the best magic in the country, and an older brother who also excelled in martial arts.Ferris, the second son of Viscount Clouren, succeeded in starting his own business at the age of 15, using the two as a cover.He wanted to hide the fact that he had reincarnated and inherited both of their supreme talents and live a peaceful life as a magic core craftsman as a hobby, but his sister and brother who doted on his younger brother wouldn't allow it!?Unable to forgive his younger brother for not being recognized by the world, his older sister keeps giving him more and more work...She was under so much pressure that she couldn't refuse, and behind the scenes of her main job, she had to make a secret move to protect the peace of the territory.Gradually becoming known to the world...?“Big sister, big brother…can you not get in the way of making magic cores?”The unconscious strongest fantasy of a reincarnated boy who wants to live a leisurely life!