A doctor who specializes in monsters. He comes from the human region in the east. The encounter with the lamia, Saphe, in his childhood leads to his interest in monsters and medicine. He's not the dependable type, but has a gentle and kind personality. Though young, his teacher Kuturiff recognized his talents and entrusts him with his own medical clinic. He's quite the workaholic, and when he gets overly concentrated on treating his patients, Saphe has to reprove him of his carelessness of going beyond his limits.

An apprentice of Kuturiff, the same as Glenn. She has deep knowledge in pharmaceutics, and supports Glenn as his assistant. Though being responsible and intelligent, her species can get quite jealous, leading to much stress every time Glenn, who she has feelings for, is approached by a new girl. She often acts out from being unable to express her true feelings. Lamia's are vulnerable to the rapid change of their body temperature and especially dislike the cold, but are able to use their tail just like their 3rd hand. By the way, Saphe is an albino and always wears a special innerwear to shut out the sunlight.

A rookie mermaid singer. She is a cheerful and innocent girl in her adolescence, who sings in the "Merrow Waterway City". She also has a pragmatic side, since her father has disappeared, and now has to take care for her mother and five younger siblings, making her very strict about money. She loves shrimp shell sausages, and even eats the shell. Her species have low body temperature, which makes them vulnerable to burns when touched by humans. They can protect their eyes while swimming underwater by closing their translucent nictitating membrane.

A clothing designer who works at "Arakinu Sewing", a large company that produces and provides clothes for monsters. She is a spider-like species called arachne. At first sight, she seems like a friendly, elegant lady, who speaks a unique dialect of the east, but actually has a "twisted bad habit". She's an old friend of Saphe's and enjoys going out for drinks together. Arachne's can only bear females, so their companions are always other species. They even set traps to forcefully make their crush their's.

A centaur who wants Glen as her future husband. She is called "princess" by her species, since she is the daughter of the president of "Scureteir Company", which single-handedly takes care of the distribution in Lindworm. Being the 3rd rank of the arena, she fights bravely with her spear in hand, but also has a cowardly side. The elegant "princess" is straight forward and hates injustice, but also is compassionate. She is a herbivorous species and only eats vegetables and fruits, but needs a great amount to sustain her large body.

A dragon with the appearance of a little girl. She is the leading person who developed Lindworm into a city where monsters and humans coexist after their war. Her voice is extremely small, and needs her aide Kumu to speak for her. Though being the most powerful monster, she is a pacifist, who loves humans. However, she also likes to watch the fights in the arena, and is known as "Ryuutoujo" (Dragon Combat Lady).

A flesh golem that is the guard of Scady. She was initially a golem made in the east for combat, but now has her own will and supports Scady whom she adores. Her body is a patchwork of corpses, which makes her fragile and needs her parts to be replaced regularly, but she hates doctors. She doesn't feel pain by losing her body parts, but she was given very sensitive thighs to suit her creator's likings. Golems are created for various purposes depending on what the creator wants. Kumu was created as an undead soldier.

A harpy girl. She was rescued by Glen when she was a captive of a slave trader. Without her parents, she grew up in the slum as an orphan. Though being aggressive and wild, she's just another cheerful girl that likes to fly going through that stage. She uses her sharp claws to hang on to unstable places such as cliffs and branches. It looks as if she has hair but it is actually a crest of feathers, which is unique to harpies. Their feathers make them a species strong against the cold.

A craftsman apprentice cyclops girl. With the chief's assurance of her ability, she is the only female in the "Cyclo Workshop". Her self-deprecating personality makes her ashamed of her distinctly large eye. She has social anxiety which makes her act weird from time to time. Unexpectedly, she is fond of gothic lolita fashion, but she tries to keep it a secret. She feels uneasy from the physical intimacy of Lulala, who has a completely opposite personality, but does not dislike being friends with her. Her species are quite handy, and are good at crafting things, such as weapons.