Father of three and youngest son of Mirel. The 13th Head of the Etam family. He first met Eirin by chance in the library and started playing 'father and daughter' with her. After she managed to suppress his berserk state, he began to see Eirin not as a 'child-play doll' but as his real daughter, feeling true love for her. Later, when Eirin went missing due to the false instigation of the spy Myla, he drew his sword in cold fury and stabbed Myla. He then used every means possible to search for Eirin, and upon hearing she was taken to an auction house, he sent assassins to devastate the place. After going through hell to bring her back, he became such a doting father that he sent multiple assassination squads to kill Duke Colin upon hearing that Eirin had been (on paper) adopted into the Colin family first. Black hair, gold eyes, incredibly handsome, Guest's husband.

The 12th Head of the Etam family. Erno's father and grandfather to the three siblings. He is a tsundere. Guest's father-in-law, he calls Guest 'daughter-in-law.' White hair and gold eyes.

5 years old. A pink lizard beastkin. Recognized as Erno's daughter, she is revealed to be a dragon and becomes the 14th Head of the Etam family. Pink hair and gold eyes.

Erno's eldest son. A boy who resembles his mother, Dalia. He researches medicine to suppress the family's unique madness. His specialties are alchemy and pharmacology. Cillian's twin brother, Guest's son. Red hair and gold eyes.

Erno's second son. A boy who resembles Erno and has a talent for swordsmanship. Black hair and gold eyes. Kalan's twin brother, very handsome, Guest's son.

The young lord of the Colin family. He grew up in an orphanage after being kidnapped as a child by someone with a grudge against the Colins. According to Duke Colin, who struggled immensely to find his son, the kidnappers were eventually caught, tortured, and buried in concrete under the sea (...). Purple gradient hair and purple eyes, wearing an earring only in his left ear.

Head of the Colin family and Richard's father. He searched everywhere for Richard after his disappearance. The kidnappers were eventually caught and buried in concrete. When he met Eirin and Richard, he tried to adopt Eirin into the Colin family, which led Erno—who was trying to formally adopt Eirin into the Etam family—to try and assassinate him. Since then, he and Erno have engaged in fierce psychological warfare, trading assassins back and forth. Long purple gradient hair and purple eyes.

8 years old. Erno's niece, but after her parents died, she was brought in as an adopted daughter because she possesses the ability to calm the Etam family's madness. She is obsessively fond of and protective of Eirin.

A white-haired, blue-eyed boy considered the next High Priest of the temple serving the main god, Arma. He is fanatically loyal to Eirin, who saved him, and voluntarily offers to be her 'dog.' He even barks like one (...). Later, he is 'picked up' by Erno, who had just finished a heated argument with Duke Colin, and now lives with Eirin.

Features: Shadow of Light. Refers to Guest as 'Master.' Human form has long black hair and red eyes. Male. Usually travels in the form of an owl.