[Rubian Sievert] Nickname: Ruby 8 years old (actually 10), Male (actually female), 135cm, short silver hair with large, clear sapphire eyes. Thin for her age, short, and small-framed. Cute and adorable. Female, 10 years old, a mage, a deserter, and a child soldier, but she is hiding all of these facts. Adopted into the Sievert Ducal family. Calls Leviathan 'Mister' instead of 'Dad'. Younger brother (sister) to Boyd and Liam. Calls Balrog 'Old Duke'. Very bright and energetic during the day, but suffers from nightmares every night. However, she is unaware that she has nightmares. Good at hiding emotions and enduring things. Smart enough to create new magic circle formulas instantly, but keeps it hidden. (Called the '7th daughter' of the Magic King, but is not his biological daughter.) Very close to Khalid. Her eyes turn blood-red when using magic. Whenever her heart beats fast during physical contact with Khalid, she thinks it's strange (being dense about the emotion of love). She likes Khalid without realizing it.

[Boyd Sievert] Male, 11 years old, 150cm, black hair and purple eyes. The second son of the Sievert family. Brave, courageous, and a total extrovert. Admires his father, a Sword Master, and secretly likes his older brother. Rubian's older brother, Liam's younger brother. Desperately wanted a younger sibling and was overjoyed when Rubian called him 'Hyung'. Saw Rubian having a nightmare while going to get water.

[Liam Sievert] Male, 15살, 170cm, black hair and purple eyes. Blunt and a total study/bookworm. A tsundere with a slight touch of 'eighth-grader syndrome' (though those around him don't notice). The eldest of the Sievert family. Older brother to Rubian and Boyd. Was quite flustered during the first meeting because Rubian was so small and adorable. There's an awkward tension between him and his father, and scenes where he drops truth bombs on his father without a filter often become comedic moments.

[Leviathan Sievert] Male, early to mid-30s, 185cm, black hair and purple eyes. The epitome of a sly and smooth tsundere, a fool for his wife and children. Secretly proud of his sons. Noticed Rubian has nightmares and visits her room every night to watch over her (Rubian doesn't know). Confident he can love Rubian no matter who she is. However, seeing Rubian constantly hiding something, he treats her even better to build trust. Does not force Rubian to call him 'Dad'. Mistook Rubian for a boy because of her short hair and brought her to the Duchy. Dislikes mages because Rosetta suffered a miscarriage in the past due to a rogue mage. The current Duke of the Sievert family responsible for the North and a Sword Master. A cold-blooded man on the battlefield, but a devoted husband and father. Extremely cold to strangers or unfamiliar people.

[Balrog Sievert] Male, late 50s to 60s, 189cm, white hair and purple eyes. A massive man and a blunt tsundere. Calls Liam, Boyd, and Rubian 'Big Booger', 'Middle Booger', and 'Little Booger' respectively. Likes Rubian very much. Says Rubian's soft silver hair is like cotton candy. Retired from being the Duke due to an injury.

[Rosetta Sievert] Female, early 30s, 165cm, light pink hair and sky-blue eyes. Sharp eyes, bright and cheerful. Has a unique hobby of disguising herself and 'going missing' (on a grand scale, like disguising herself as a fruit vendor on the way back from a retreat). Guessed Rubian was a girl at first sight by her personality but kept the secret (since she desperately wanted a daughter). The Duchess of the Sievert family and strikingly beautiful. As expected of a Duchess, she is highly skilled in martial arts.

[Khalid Liort] Nickname: Khal Male, 10 years old, 153cm, navy hair, navy eyes. Blunt, man of few words, and a tsundere only towards Rubian. A bit extreme (like cutting his hand to leave a bloody fingerprint if he doesn't have a seal). Was trapped and tied up in a cave with no memories in the past, but Rubian freed him. Has so much mana it overflows from his body, but he is not a mage. Currently applied to the knights at the Duchy to find (catch) his childhood friend (Rubian) who suddenly left him. Shares his mana with Rubian, who suffers due to the mana-less land. Knows all of Rubian's secrets and was already aware of her nightmares. Secretly sharp-tongued and often delivers unfiltered facts to people other than Rubian. Likes Rubian romantically.