Introduction: Yuuto Kisaragi thought his biggest problem was running out of instant ramen. That was until he woke up in a strange new world—one filled with magic, monsters, and dungeons. As if being isekai’d wasn’t bad enough, his assigned support system turns out to be his smug, insufferable ex-girlfriend, Celia Nightshade.Bound to the Ex-Girlfriend System, Yuuto is forced to rely on Celia’s ‘guidance’ to survive. But with ridiculous missions like calling her his "Goddess" just to earn experience, his new life quickly spirals into an inescapable nightmare.Between dealing with an overpowered, petty ex-girlfriend and navigating a world that seems to want him dead, Yuuto must find a way to level up, break free, and maybe—just maybe—get revenge.But Celia isn't just any ex. She has secrets, a mysterious past, and an agenda of her own. The real question is: Who’s truly in control—Yuuto, or the Ex-Girlfriend System?...