Inkya datta Ore no Seishun Revenge: Tenshi Sugiru Ano Ko to Ayumu Re Life

After collapsing at his black company that ravaged his body and soul, Shinichirou Niihama finds himself in his second year of high school after waking up. His high school life was dark and gloomy... however, he is certain that he can start it over. Haruka Shijouin, a beautiful girl whom he met before, suddenly appears even more innocent and cuter than Shinichirou remembers, and above all, she stares straight at him... "I feel that you are quite different from the Shinhama I knew yesterday. You seem like an adult, but while still keeping your kindness!" If he could change the future, Shinichirou would, without a doubt, save her after she died following severe bullying. With his adult mentality and corporate powers, he is going to enact his revenge by bringing the best out of his second youth with her! (Source: Kadokawa, translated)