Not a BL and I feel it's misleading to market it as a romance. There was maybe potential for that but then you learn the angel is around 16 while the adult is in his 30s. It felt more like big and little brother to me. Seemed like a redemption of sorts for Koki's guilt about his own little brother.

Heartwarming and heartbreaking with an ending that is hopeful and really sad at the same time.

General Spoilers below.
It started somber but with some lovely understated humor and then got really heavy. It did get more positive and hopeful but it was heartbreaking at the same time because the angels's wings filling in meant he would leave at some point. The very last couple shots were weird and not satisfying; it seemed to imply an open ending but just left me confused.

It's too heavy and unsatisfying for me to watch more than once but it was well done, and well acted. I'm glad I watched it once as it did have some poignant messages handled in a tactful way.

Trigger warnings for accidental death, suicide, violence, and bullying.