Vania

Vania (ヴァーニア) is a side character of the Slime Taoshite 300-nen, Shiranai Uchi ni Level Max ni Nattemashita series. She is a Leviathan demon and the air-headed, absent-minded younger sister of Fatla, and serves as Beelzebub's assistant in the Ministry of Agriculture in the Demon Kingdom.

Background
Prior to the events of the story, Vania and her sister served Beelzebub as secretaries. Not much else is known.

Vania made her first appearance alongside Fatla in Chapter 18, A Leviathan Dropped By, where she and her sister arrived in Flatta to ferry Azusa and company to the Demon Kingdom. Her sister took the form of a massive leviathan with a resort on her back while Vania serviced the guests, however due to her absent-mindedness she ended up inconveniencing Falfa and Shalsha by giving them spicy food. On the return trip, Vania and Fatla switched roles, proving to be a bad idea as she remembered a joke that caused her to chuckle and shake the resort. However she proved to be a hard and dedicated worker nonetheless.

Appearance
Being a twin, Vania looks almost exactly, if not entirely, like her sister. Like most demons, her human form is mostly human of slim yet well endowed proportions and beautiful features, with the notable addition of a pair of fish wings on her crown. She has straight, presumably brunette hair that reaches down to her waist.

Her uniform consists of a long vertically-lined dress-cum-dress-shirt with a tie and a formal jacket with puffy shoulders and large white cuffs, opened from the collar to the navel allowing her breasts to flop out.

As per her status as a Leviathan, she can also transform into the gargantuan beast, which is the same as her sister's, which was described as, "something unbelievably huge, something beyond enormous, was blocking out the sun." Presumably, it is very big.

Personality
Though a natural air head and rather unrefined character, Vania proves to be a hard, energetic worker in spite of this quality, servicing Azusa and company diligently during the trip to the Demon Kingdom. She's also very loyal to Beelzebub as she and her sister accompanied her and a childish Azusa to the World Tree.

Unlike her sister, she's not one for formalities or strict adherence to protocol, instead speaking to many guests rather casually and confidently, as well as indulging in the restaurants and facilities while on the mission to the World Tree.

Powers & Abilities
Vania hasn't demonstrated many abilities outside of her initial appearance, where she and her sister assumed the forms of massive Leviathans to and from the Demon Kingdom. While they could both fly in these forms, it's unknown if they possess the ability in their human forms.

Trivia

 * The Leviathan is a sea creature in Judeo-Christian folklore, appearing in several Hebrew books, that being Job, Isaiah and Enoch as well as several Psalms. It is serpent-like, capable of breathing fire (breathing fire was symbolism of Hell residing in a creature) and possessing indestructible scales as described in the books, and in Christianity is identified as one of the Seven Princes of Hell
 * The Book of Isaiah 27:1 and later Jewish sources describes the Leviathan as a dragon, which is alluded to in the chapter A Leviathan Dropped By, where Shalsha informs Azusa of the theory that Leviathans may be or related to dragons (idk if this was intentional)
 * Similarly, Azusa's misapprehension about Leviathan's being sea creatures is corrected when Beelzebub informs her that they submerge themselves when on vacation, likely the origin of the impression