What if you could become invisible...?

*Note: The sixth (and supposed, last volume) hasn't being published yet, having some chapters not collected in a volume release.*

*Note: Includes 2 extra chapters.*

Irene, a \[human\] girl, falls in love with \[elf\] Vivian. But Vivian's answer is "NO." What is the reason for her stubborn rejection? (Source: Harta, translated)

A young boy watches as an old man traps a stray dog. The kid is somewhat traumatized by the commotion, and the old man says that with wild dogs, which can turn vicious, sometimes you just have no choice. The old man turns out to be a former kamikaze pilot who hadn’t been given his final orders before the end of War. He’s now an animal control officer, and a habitual alcoholic. As time goes by, the boy starts spending more time with the control officer.