Machigatteita no wa Ore Datta n da.

Synopsis

Furuya has finally escaped from his yandere girlfriend Sara. It was so simple—all he had to do was kill her. But it seems that not even death can separate them, as she lingers as a ghost due to her regrets. Back when Sara was alive, Furuya felt her looming presence at every turn; now, as a spirit, she is like any normal girl. Perhaps he had misinterpreted her the whole time. As his guilt piles up, Furuya feels like he has to atone for his actions—but at what cost? (Source: MyAnimeList)