Abysalyounglord
You can make him go from high school dxd, years before canon, so for example he could get close to Morgan and have a sorcery partner, save Koneko and Kuroka, and even wake up Ingvild Leviathan, who suffers from sleeping sickness and has one of the most broken Longinus class Sacred Gear in the "Nereid Kyrie" series, which allows him to control dragons and anyone who has or uses powers that have to do with dragons, imagine how broken the protagonist would be once he copies that power and trip to fairy tail 🤔 (IMAGEN: Ingvild Leviathan)