Shirakawa You

He has an older sister who is the best magician in the country and an older brother who also excels in martial arts. Ferris, the second son of the Viscount Clauren family, succeeded in becoming one at the age of 15, using the two of them as a cover. He thought he would hide the fact that he was reincarnated and inherited both supreme talents, and live peacefully as a hobby magic nucleus craftsman, but his older brother, who doted on his younger brother, would not allow it! The older sister, unable to forgive her younger brother's lack of recognition by the world, kept assigning him more and more work.... She was so overwhelmed that she couldn't refuse and had to work behind her back to keep the peace in her territory. Gradually, his name becomes known around the world and...? "Sis, bro... can you please not interfere with the making of the magic nucleus?" A fantasy of a reincarnated boy who wants to live a leisurely life!

An old man is forced to retire from the adventurer's guild and decides to return to his hometown. On his way, he picks up two babies; the first one is a human baby with the emblem of a hero, and the second was a baby of the demon tribe with the emblem of the demon king. And so the story of the old man who picked up the hero and the demon king begins. Link : WN Raw