Tatta Hitori no Kimi to Nanajuuoku no Shinigami

A strange ring of light, known as the Ray Ring, has encircled the Earth for 15 years, occasionally releasing enigmatic objects called RUMs that create minor disaster zones. These events are predictable and contained, leading most people to disregard them. Seita Tooki, an ordinary individual, is unexpectedly confessed to by Awayuki Kujou, his long-time rival. Before he can respond, a RUM suddenly falls, assesses the scene, and kills him along with everyone in the surrounding city as collateral damage. It is later revealed that the Ray Ring is inhabited by 7 billion Grim Reapers, most of whom aim to reject their recently discovered romantic feelings.