When her father moved abroad for work Yui is forced to live with six vampires. Yui has a cheerful and optimistic personality, but can also be somewhat naive. She can be oblivious to certain things and indecisive when making certain decisions. Yui has wavy platinum blonde hair that falls down to her shoulders with her bangs parted in the center, and a pink flower hairclip pinned on the left side of her head. Her eyes are a light glistening sherbet pink color. She's pretty and cute. Yui wears a pink top with sleeves that fall off her shoulders. It is decorated with black straps and a black cross-stitched decoration with black ribbons at the end. She wears it with brown shorts and brown boots. She also wears a gold heart-shaped necklace.

The third son (biologically the fifth) of the Sakamaki household. Ayato is a narcissistic prankster who has an obsession of being the best due to his upbringing by his mother. Known as the troublemaker of the household. Ayato along with Laito and Kanato, whon are triplets. Ayato is a slender young man with unruly, reddish-colored hair spiked at the ends, narrow green eyes, and a fair complexion. He looks down on others and loves to bully and tease people, bragging about himself and sometimes commanding everyone to call him "Ayato-sama". He refers to himself most of the time as "Yours Truly" and refers to Yui as "Chichinashi"

The fifth son (biologically the third) of the Sakamaki household. Laito is extremely perverted. His perverted nature causes him to be suspended from school often. He is always cheerful and loves to joke and is similar to Ayato when teasing Yui who she calls "Little Bitch".Laito has shoulder-length reddish-brown hair, with a lighter blondish color to the tips, a mole on the right side of his chin and green eyes just like his triplet brother Ayato. He has fair skin and has a slender figure and is often seen smirking. He has two piercings on his left ear.Laito is extremely perverted. His perverted nature causes him to be suspended from school often. Laito is an extreme sadist.

Kanato appears to resemble his mother Cordelia, having the same colored light purple hair, though he has large matching eyes, with visible dark undertones beneath them, most likely due to lack of sleep. Kanato also has a rather short, thin figure with a noticeably younger look about him than his brothers, thus causing him to stand out as more childlike in appearance.Kanato is almost never seen without his beloved Teddy wrapped safely in his arms.Kanato's disturbed, childlike personality is a fact and he has had a very weird and eccentric personality even as a child, usually staying alone, talking to his dolls, self-harm, or turning others into wax dolls.Around others, Kanato usually acts very spoiled, childish, and demanding, usually emotionally blackmailing others, either with tears or hysterical tantrums to get his way. In fact, Kanato is quite mentally unstable and shows signs of psychotic behavior when angered. He is shown to be moved to tears easily which can quickly be replaced by loud yelling. He adores sweets and hates things that are bitter.

The sixth and youngest son of the Sakamaki household. He is usually alone and never cares about what's happening around him. Subaru is the silent type who usually sleeps in a coffin, which is also inside his room.Subaru is a handsome young man with silverish light-lavender whitish hair, l He also portrays scarlet red eyes with a slight pinkish hue. Subaru can be described as the loner type. He is usually alone and never cares about what's happening around him. Subaru is the silent type who usually sleeps in a coffin, which is also inside his room. However, due to his very traumatic childhood, he is easily angered and resorts to violence quickly, going as far as to break everything when he gets extremely angered. There is a tsundere side of him that not only Yui can see but also his brothers, and he usually gets teased about that by Laito.

The first and eldest son of the Sakamaki household. He is also the current master of the mansion. Shu is usually seen sleeping in the living room and has been held back once as a senior in high school.Despite Shu being the eldest son, he doesn't take any responsibility to look after his five brothers and the house instead mostly complaining about how he has to "deal with their problems." He mostly pushes this job to Reiji.

The second eldest son of the Sakamaki household. Reiji has refined manners. Although he might have a polite, sophisticated way of speaking. He values rules and demands that they are followed by others.Reiji is a handsome, tall, slender young man with pale magenta eyes and pale skin. His hair is a dark purple plum colour which fades lighter towards the tips, the very tips of the hair around his face and neck becoming a light blond. Although Reiji is the second son, he takes it upon himself to manage the Sakamaki family as if he were the eldest son. He cleans the house, manages household affairs and funds, and keeps his brothers in line. His role in the family combined with his gentlemanly behavior often causes him to appear more like the eldest instead of his older brother Shu.