The Optimal Solution to Eventually Becoming the Mastermind やがて黒幕へと至る最適解

After losing his beloved master Artesia, Kalts swears vengeance upon those who betrayed her. With every preparation complete, he activates his “return” and rewinds time—awakening in his ten-year-old body once again. Armed with knowledge from the future, he begins his calculated rise as the true mastermind behind the scenes. A dark fantasy tale of cold intellect, revenge, and destiny, where the boy who once served now becomes the puppet master of fate.