AppearanceEditShe has long bright reddish-pink hair, pointed ears and a long snake-tail of the same color. Her eyes are Amber with slitted snake pupils, a normal trait for lamiae, though it becomes much more prominent when she's mad or under the effects of a full moon. Her ears are very long and pointed and she she has vestigial scales on her cheeks. She has a very long tongue and is also seen with small fangs on occasion. The length of her tail is never fully established, and varies throughout the chapters between 12 feet to 20 feet.
PersonalityEditShe is incredibly enthusiastic about the smallest things, having a very bubbly and slightly child-like nature. She is also very flirtatious, trying to seduce Kurusu on multiple occasions. When Kurusu told her and Cerea to think of Suu as a child, she briefly fantasized of having had a child with him.
She is very protective of Kurusu, becoming very irritated whenever one of the other girls makes a move on him. Under the effects of a full moon, however, she lost much of her reasoning, acting almost solely on her instinct and feelings for Kurusu, going so far as to be willing to allow Centorea and Papi to join in while having sex with him, so long as she could be with him.
However, despite her naturally cheerful demenor, Miia is not as emotionally mature as she would appear. She has, on a few rare occasions, become upset and angry at other people to the point of almost striking them with her tail, and when Papi and Centaurea moved in, she became a little more clingy and jealous.
Skills and TraitsEditDue to being half-snake, she is naturally skilled at climbing trees. Since she is part reptile, she is also a poikilothermic.The tip of her tail is shown to be very sensitive.
At a certain time, like a normal snake, she starts shedding her skin, which according to her, is more embarrassing then being seen naked.
She is also strong enough to crush metal pipes without noticing when under the effect of a Full Moon.
Miia is placed with Kurusu as part of the "Cultural Exchange Between Species Bill" by Sumike, despite his not actually being a part of the program. At first she thought that he would be afraid of her, since she was half-snake. However his kindness and effort put into making sure she was happy (to the point of remodeling many parts of his home for her convenience) quickly impressed her.
As time passed, Miia eventually fell in love with him. Although Kurusu appears to feel the same way, there is a stipulation in the exchange program that prohibits interbreeding between humans and beast creatures. Violating this law would result in Kurusu being severely punished. This doesn't stop Miia from making advances on him whenever she gets the chance, however.
Later on, when Papi became a resident of the house, Miia thought she was just a child and didn't believe she had to worry about any competition; however, upon finding out that Papi was as old as she is, she quickly changed her attitude and warned Papi to "keep her hands off him".Later, Cerea became the third resident of the house, much to Miia's dismay. She tried to assert her dominance over the group by claiming that as the first resident of the house, only for a fight to break out between the three in the park; Ms.Smith quickly got involved and tried to shoot them with her tranquilizer gun in order for them to not accidently injure anyone, including themselves, only for Kurusu to take all three shots unknowingly. Miia and the others later apologized for their behavior. 
At one point she tried to cook for Kurusu, only for her skin to start shedding; much to her embarrassment, Kurusu was forced to peel it off for her, and she tried to award him with her food, only to find out that it made Papi and Cera very sick due to her simply guessing on how to make it instead of reading a cookbook. Later on, Kurusu started teaching her how cook properly, only for them to be interrupted by a Slime Girl springing out of the pot, temporarily knocking her out. After Kurusu reverted her to a more harmless state, she, Cera, and Kurusu were left puzzled on what to do with her. 
Later on, the Slime Girl (Now named Suu) continued to cause trouble around the house, accidentally adsorbing many objects around the house and getting slime everywhere, much to their dismay. While the two of them are angry at her, they are surprised when Suu slowly learns to talk. They then start talking about bringing her to Ms. Smith; however, when Miia points out that Suu probably didn't come here legally and she could be put in prison, Papi quickly leaves with her. Miia and Cerea try to go after her but are stopped by the arrival of Ms. Smith.
Later on Miia talks with Kurusu on the phone about Suu staying with them. At first she and Cera are hesitant about Suu staying, but they quickly change their minds when Kurusu tells them to think of her as a child, with Miia even thinking of a having a baby with Kurusu someday; however, when Kurusu arrived home, Miia told him a little too late that Ms. Smith had arrived, culminating in the encounter with Ms. Smith they had wanted to avoid. 
Almost immediately Miia, Cera, and Papi started panicking over what Ms. Smith would do to Suu, but Kurusu was too busy with the remodeling of his home to pay too much attention. Despite him thinking the remodeling was for Suu, the the of them took her and hid in the park, all the while hiding from what they thought were Smith's "minions" (in reality they were Meroune's escorts). 
- Her name is derived from her species name: "Miia" from Lamia
- According to Sumike, Lamia are an all-female race, as are some others such as Harpies.
- Miia has several traits similar to other anime/manga characters:
- The way she refers to Kurusu as "'Darling (ダーリン, Darling)" is very similar to how Lum refers to Ataru in Urusei Yatsura.
- The tip of Miia's tail is very sensitive, much like Lala from To LOVEる.
- Miia somewhat resembles Chizuru from Kanokon in personality.
- In Chapter 10, she wears a military uniform, an eyepatch, and a beret with a FOX emblem, a clear shoutout to Metal Gear Solid, specifically the character Naked Snake/Big Boss from Metal Gear Solid Portable Ops.