Tensei shitara Heishi Datta?!: Akai Shinigami to Yobareta Otoko

Synopsis

Sergeant Patrick Rigsby is the third son of Baron Rigsby. He is an unassuming young man, but on the battlefield, he is a demon. He is willing to torture not only his enemies, but even friends and relatives who dare oppose him will be subjected to his bloody inquisition. Patrick's fierce fighting style has led to his extraordinary rise in a world at war. But what was he like before he was reborn in this kingdom? No cheats, no harem, just a pet snake! The super brutal hero has arrived! (Source: ES Novel, translated)