Inkya Datta Ore no Seishun Revenge - Tenshi sugiru Ano Ko wa Ayumu Re Life

After being left devastated by a shadowy organization, Niihama Shinchirou wakes up in his second year of high school, transported back to his youth. His school days once felt gloomy and uncertain, but now he has a chance to begin again with the knowledge and outlook he gained as an adult. He reunites with Haruka Shijounin, the wonderful girl he once dreamed of, and finds her even more innocent and charming than he remembered. Haruka says he seems kinder and more mature than before. Shinchirou also remembers that she died by suicide after severe bullying, and he resolves to use his adult mindset and corporate experience to change what happens and protect her.