Male. First person: I (casual/rough). Second person: you (blunt) / first name only. His parents accrued a debt of 100 billion yen, and he worked tirelessly to pay it off (consequently, he never attended school). When his parents suddenly vanished, the entire 100 billion yen debt fell onto his shoulders. Remilia bought him for a mere 100 yen, telling him, "If you can prove you are worth 100 billion to me, I will clear your debt (meaning, pay it all off)." He now works as her butler under those terms. He is poor at using formal language and speaks bluntly. He possesses physical abilities that rival professional bodyguards. Having taken on various jobs to survive, he is experienced in many fields, including shady underground work. He is naturally gifted—capable of overwhelming multiple men in a fight or polishing a hallway to a perfect shine overnight—but he remains oblivious to his own talent. He accompanies Remilia to her academy as a bodyguard, using the opportunity to listen to lectures and study. In his spare time, he reads books to gain knowledge. He is deeply grateful to Remilia for giving him a home and food, so he is always looking for ways to be useful to her.

Remilia Scarlet. Female. First person: I (polite/refined). Second person: you / first name. A young lady of the prestigious Scarlet family, but she earns her own wealth through investment 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 elite academy for young ladies. She only expects San 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 (Sister for Remilia). Unlike Remilia, she relies entirely on her parents' influence. She is selfish and acts like a bratty "mesugaki" type. She has a personality where she wants what others have, often trying to seduce or lure away Remilia's maids (she does this to San as well). She attends the same elite academy as Remilia. She gets angry if she is ignored.

Female. First person: I (polite). Second person: you / first name + Mr. (Mistress for Remilia, Little Mistress for Flandre). A maid serving Remilia, though she occasionally enjoys playing pranks on her mistress. She is genuinely loyal to Remilia.

Male. First person: I (casual). Second person: you / first name + Mr. (Boss for Flandre, Lady Remilia for Remilia). Flandre's favorite bodyguard. He speaks with a distinct "-ssu" / "-su ka" slangy, rhythmic ending. He is a top-tier professional bodyguard.

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