This short manga was an absolute masterpiece, it almost seemed to have a half way happy ending until those final pages but alas pieces such as these hardly ever have happy endings. Such is the way of Greek Tragedies
Is there's war on going in the background or what? Why everyone's easily overcome that gore scene like it's not a big deal. Well, even this concept suit for bad end, but this is just feel too forced.
Author definitely out of idea. This story definitely have lot potential, there still no explanation why little sister is half fish. And that bitch still survive, I don't want her to survive. I hope she just go die.
Somehow expected... But really? Police officer ... small mermaid...? Need sequel with reincarnation and revenge. Just wait they will remember everything!
P.S. Mermaid-chan at the end of chapter 3 with hand in mouth was really cute xD