Kyô no Kira kun (2017) online

Ninon Okamura and Yuiji Kira live next door to each other, but they have not talked with each other at school. Ninon Okamura learns from her parents that Yuji only has a year to live. One day, Yuiji Kira tells Ninon Okamura that he doesn't want to die and he doesn't to be alone. Ninon Okamura tells him that she will be by his side until he dies