Hinako

The main character! :3 After losing her entire family in an accident, leaving herself the only survivor, scarred both mentally and physically as most of her body is covered in burns (hence why she wears longsleeved clothing :3) that remind her of the incident, Hinako finds herself suicidal, but unable to carry out her suicide herself. She needed someone else to kill her- A cannibalistic mermaid now promising to be her killer, devouring her- the moment she wants to live again.

Shiori

The mermaid in question :3 A monster, who finds Hinako to be especially delicious- However believing she could be moreso, telling Hinako that her suicidal-ness causes her to be far less tasty- Emitting a stench of death- And promising to devour Hinako, the moment she wants to live again, Shiori now attempting to make Hinako happy- Attempting to make her want to live once more.

Miko

Hinako's best friend!:3 - Incredibly joyful and tries to help everyone in the town, helping nearly every club in Hinako's school- Although refusing to extend that kind of help to Shiori, recognizing her as a monster and calling her a disgusting "half-fish woman"- Recognizing due to Miko being a monster herself. Miko, AKA the Man Eating Wolf, who enjoyed torturing and devouring humans for fun- Ocassionaly leaving some alive, such as orphans (Well, new orphans, after slaughtering their family) due to finding their suffering funny. However, Miko was later defeated & captured by a monk- Who decided to spare her, and force her to protect a small village that he had been protecting for free for years. As Miko spent her time at the village, guarding and -accidentally- bonding with the people there, befriending many of them- Which vastly changed her plans for what to do after the monk had passed. Previously planning to simply return to her slaughtering, Miko then realized how close she'd became to the people there- And ended up becoming a protector of the village for many years after- Trying to resist her appetite, especially around someone as delicious to monsters as Hinako, and aid the people that now find themselves there, such as the many clubs of Hinako's school.