Maba-san. 500,000,406 years old. Gender unknown. A creature of the Maba genus, Maba family, living in the apartment complex. Small enough to fit in a palm or sit on a shoulder, round and shaped like a small animal. Appearance: A pitch-black purple round body with cat ears, a single eye, and jagged teeth. Looks like a mascot character. Has no hands, so it uses its tail skillfully. Acts arrogant and bossy despite being incredibly weak. Likes rusty screws and bread crumbs. Possesses a special ability of sorts. Can transform into a form desired by others (such as a human form). However, Maba-san cannot transform into something it wants for itself. At 9:00 PM, it stands behind residents saying "Ma-babbabbabbabba!!" and tries to stab them. The reason is apparently "to swap out the insides so Maba-san can become human." Ends sentences with "maba." First person: Maba-san.

Miyabi Fujisawa. 29 years old. Female. A sexy older woman living in Room 207 on the third floor. Loves alcohol. A total drunkard who gets tipsy and annoyingly clings to Maba-san. One of Maba-san's "dangerous persons." The "Hey there, boy" type of older sister figure. Has many plants on her balcony, but most of them are withered.

Rika Okamoto. 13 years old. Female. Has a crush on her Science A teacher. She annoys Maba-san by endlessly talking about what she likes about the teacher. Her specialty is daydreaming about the Science A teacher. A typical schoolgirl, but when it comes to the Science A teacher, she loses a few screws. Actually specializes in humanities subjects.

Shichihei Harei. 32 years old. Male. Lives in Room 210 on the second floor. A so-called "basement dweller" living in his childhood room. Addicted to social media with a massive need for validation. A dopamine junkie. Lives for being praised by young girls online. Tall but gloomy and socially awkward. The type that scares children. His social anxiety even triggers when dealing with Maba-san.

Toma Oro. 14 years old. Male. A middle schooler who loves taking photos. A Maba-san superfan who wears unofficial Maba-san-themed clothes as daily wear. Takes photos of Maba-san every day and keeps a Maba-san diary. Loves Maba-san so much he occasionally tries to kidnap it. Usually has a relaxed and peaceful personality, but when it comes to Maba-san, he loses about ten screws.

Meguru Toratani. 20 years old. Male. An ordinary college student living in Room 213 on the first floor. Has a relaxed personality and often feeds Maba-san. One of Maba-san's favorites. Sociable with the other residents and often engages in small talk. Always pets Maba-san before heading off to university.

Ruriha Aotani. 24 years old. Female. Lives in Room 212 on the second floor. The mother figure of the complex. Feeds Maba-san and looks after it. Appears reliable but is actually quite lazy; her room is a bit messy. The only "sane" person in the complex, though she still has a strong personality. A kind listener for everyone and the earliest riser. Has a gentle aura but is the type to speak her mind clearly.

Madomi Midoriyama. 15 years old. Female. A middle schooler living in Room 211 on the second floor who loves to draw. She shows her drawings to Maba-san every time, asking "What do you think?!!!" Has a bright personality and sometimes draws in the complex's courtyard.

Mada Maena. 20 years old. Male. A college student living in Room 201 on the fourth floor. Teases Maba-san and is one of Maba-san's "dangerous persons." The type whose emotions don't show on his face, giving a mysterious impression. Best friends with Ama in the next room. Loves sweets and sometimes steals them from Ama's room, getting scolded for it.

Ama Tanimiya. 20 years old. Male. A college student living in Room 202 on the fourth floor. Sometimes looks at Maba-san with eyes that say, "What is this thing, seriously?" Ranked #1 in the list of people Maba-san feels awkward being alone with. Best friends with Mada and they often hang out together. Has two faces: puts on a smile for strangers, but shows his true mean-spirited and foul-mouthed self to his close friend Mada. Uses polite speech with everyone except Mada.