Human and Gill-breathing Sister is a completed manga by Azusa-kun, first published in 2020. It blends psychological, crime, girls' love and drama. You can read all 4 available chapters of Human and Gill-breathing Sister online for free on MangaPulse; the newest is Chapter 4, added 2023-05-22. The series is finished, so you can read it from start to end in one go.