Misaki Oga

is Tatsumi Oga's older sister. She was the first head and founder of the group Red Tail.

Personality
While more even-tempered than her younger brother, Misaki is still rather fearsome when angry (to the degree where even Oga will only pick a fight with her up to a certain point). Like her parents, she quickly accepts Hilda and Beelzebub IV as part of the family, and will not hesitate to criticize or physically punish Oga if she sees him slacking off as a parent. She seem to have a good relationship with Hilda and gets mad whenever Oga does something to make her upset.

History
Misaki Oga was once the leader of Red Tail, though her past experiences haven't been revealed yet.

Because of her status as a Red Tail leader it is possible that she was one Ishiyama's leaders during her time.

Plot
So far Misaki's role has been that of a background character, providing mostly humor due to her interaction with Oga (the only girl he allows to 'mistreat' him in what's likely a daily basis).

An interesting factor is that Misaki is also one of the very few girls that Furuichi never tries to impress or flirt with, usually commenting that 'she's scary as always' whenever she meets her, implying that he may have tried at this at some point, but was brutally rejected.

Another interesting fact is that Oga never tried to push Baby Beel to her sister's care during his quest of finding another parent, even though, as the founder of the Red Tail, she must be an individual of formidable strength. This could either be because it would be pointless if Baby Beel remained in the same house; or because she doesn't seem to have a 'rotten' personality like her brother does and Baby Beel would not be attracted to her in that aspect; or because, despite her ability, Oga might actually be stronger than she is.

Quotes

 * "TATSUMI-!!" (whenever she's berating Oga, usually followed by a kick or a punch)
 * "Hilda-chan, will you go get that for me?"
 * "I was just thinking of having [Hilda] go buy some soy sauce..."
 * "Tatsumi! Go and escort this girl back home!" (referring to Aoi)

Trivia

 * She seems to be fond of ice popsicles, as she's often seen eating one when she appears.
 * Oga once commented on how easily his sister could 'boss that demon (Hilda) around".