After Losing My Weakness, I Went Against the Path of Immortality

A mortal is at the bottom of the world of cannibalism, climbing up inch by inch with calculations that surpass those of monks and madness that is not afraid of death. He can calculate everything, grab resources, and become stronger step by step, but he lost the person he wanted to save at the beginning of the story. From then on, he lived with a question without an answer. The only thing that didn't turn him into an evil spirit was the smiling, fearful and determined brother beside him.