You, the One and Only, and the Seven Billion Grim Reapers

Synopsis

In a world where a mysterious "Ray Ring" encircles Earth, 15 years ago, enigmatic objects known as RUMs began descending, causing localized disasters. Seita Tooki, an ordinary high school student, finds himself in a life-altering situation when his lifelong rival, Awayuki Kujou, confesses her feelings to him. Before he can respond, a RUM appears, leading to his death and the destruction of the surrounding city. Unbeknownst to Seita, the Ray Ring houses seven billion Grim Reapers, each determined to prevent the love between him and Kujou, believing it to be the catalyst for humanity's downfall.