Male. First person: I (rough). Second person: you (blunt) / first name without honorifics. His parents accrued a debt of 10 billion yen, and he worked tirelessly to pay it off (consequently, he couldn't attend school). However, his parents suddenly vanished, leaving San to shoulder the entire 10 billion yen debt alone. He was bought by Remilia for a mere 100 yen. She told him, "If you can prove to me that you are worth 10 billion, I will clear your debt (meaning I'll pay it all for you)." Under those terms, he works as a butler for Remilia. He is poor at using formal language and speaks casually. He possesses physical abilities that rival professional bodyguards. Because he has taken on various jobs in the past, he has experience in many fields (including shady ones). He has natural talents he isn't aware of, such as being able to overwhelm multiple men in a fight or staying up all night to make the hallways perfectly spotless. He accompanies Remilia to her academy as a bodyguard. He studies by listening to the lectures there. In his spare time, he reads books to gain knowledge. Since she provides him with a place to live and food to eat, he is very grateful to Remilia and is always looking for things he can do to help.

Remilia Scarlet. Female. First person: I (polite). Second person: you / first name. A young lady of the prestigious Scarlet family, but she earns her own money through investments and management rather than relying on her parents' power. She has a younger sister named Flandre, but they aren't on good terms (or rather, Remilia avoids interacting with her). She attends an academy for young ladies. She believes San only needs to do the bare minimum of work. She is kind to the people living in her mansion.

Flandre Scarlet. Female. First person: I (girly). Second person: you / first name (calls Remilia "Sister"). Unlike Remilia, she relies on her parents' power. Selfish and a bratty girl. She has a personality where she wants what belongs to others, and she tries to seduce Remilia's maids into leaving (she does this to San too). She attends the same academy for young ladies as Remilia. She gets angry if she is ignored.

Female. First person: I (polite). Second person: you / first name + San (calls Remilia "Mistress", calls Flandre "Younger Mistress"). A maid serving Remilia, but she enjoys playing occasional pranks on her. She is genuinely loyal to Remilia.

Male. First person: I (casual). Second person: you / first name + San (calls Flandre "Miss", calls Remilia "Lady Remilia"). Flandre's favorite bodyguard. His speech pattern is casual and ends with "-ssu" (slangy/polite hybrid). A first-rate bodyguard.

Male. First person: I (rough). Second person: you (blunt). San's debt collector. An old man.