Yatsume

Yatsume is a Lamprey Mermaid. Originally participating in the Inter-Species Cultural Exchange Exposition looking for a host, she eventually wound up sharing a residence with three other blood-sucking Liminals.

Personality
Yatsume is a sweet and reserved person and gets along well with all of the other blood sucker girls. Because of her meek nature, both Yatsume and Curie believe they have much in common and can be good friends. However, she has shown to be wary of Leechi, as the Leech girl presumably triggers primal fears in Yatsume if they're both in the water.

Despite her shyness, Yatsume has a very perverted side hidden underneath the surface. When she heard that Leechi is a hermaphrodite, and therefore has male genitals, Yatsume became very excited and could not restrain her desire to see Leechi's penis. Upon seeing it, she shamelessly complimented and praised how manly and strong Leechi's penis looked, showing just how horny Yatsume really is.

Yatsume also seems to be a bit self-conscious about being a Lamprey, believing that most humans think they're repulsive beings.

Skills & Traits

 * Cooking: Due to being the only one of the Blood Suckers to have a much more varied diet besides blood, Yatsume makes most of her meals herself. Because of this, she is a very good cook, able to make a variety of delicious foods such as liver stir-fry, European blood sausage, and liver pesto.
 * Lamprey Mermaid Physiology:
 * Fangs: Due to her Lamprey nature, and primarily blood-based diet, Yatsume's teeth are exclusively large fangs. She can easily draw blood with them to feed, though this is naturally very painful for her victim.
 * Eel Tail: As Lamprey Mermaids are closely related to Eel Mermaids, Yatsume can use her long tail to slither across land like a Lamia. This eliminates the need for a wheelchair that most Merfolk require.
 * Water Source-dependant: When hunting for a dwelling in Tokyo, Yatsume mentions that a pool (or similar water source) is imperative for her.

Zoological Classification
Lamprey Mermaids are a mermaid subspecies closely related to Eel Mermaids. While they are known for their preferred diet of suckling blood from other beings, Lamprey Mermaids can subsist on the same diet as conventional mermaids.

In Japanese folklore, lampreys are called "Yatsume-unagi" (八つ目鰻, "eight-eyed eels"). The name is derived from the seven external gill slits which line each side of a lamprey's head section which, along with their actual eye, makes it look like they have eight eyes on each side of their face. Folklore in some other countries include the lamprey's nostrils in the count, calling them "Nine-eyed Eels" instead.

Trivia

 * Yatsume's name is in reference to the word "Yatsumeunagi", which is Japanese for "lamprey eel".
 * Okayado states that the chapter where Yatsume, Leechi and Mosukii first appeared in Chapter 49 and Chapter 50 were very incomplete when they were released, and as an apology, he asked fans to choose to be one of the male background characters that appeared in the chapter (that's why they all had numbers). He added them in the final release of the volume, along with fixes on the three girls: a more gyaru appearance for Mosukii + two more arms; a more shiny appearance to her skin and suit for Leechi + some sort of eye emojis on her face; more makeup for Yatsume (lipstick, rouge, etc).