Leviathan is a main character in the yuri series Seven Mortal Sins. A mighty Demon King that controls the power of water. Her juvenile gestures of a spoiled child are very popular among her believers, and some of the most enthusiastic followers even outrageously call her “Levia-tan”.
- She won't forgive Lucifer if dates date someone else.
- She adored Lady Lucifer as her idol ever since she was young. Like her name suggests, she is a very jealous person with Lady Lucifer often being the target though Leviathan's jealousy isn't limited only to the fallen angel.
- Sometimes, her hand can reach to touch Lucifer who would prevent her from doing so.
- She always longs to meet Lucifer with heart symbols in her eye lens.
- She feels dreamy that her she blushes with her eyes shining when her face was placed on Lucifer's breasts.
- After Lucifer makes a brief stop in a high school church on Earth. Once there, she is met and fawned over by Leviathan.
- As Lucifer and Maria partake in the luxuries of their new quarters, Leviathan tries her best to gain her new mistress' favor, but grows increasingly jealous when Lucifer pays more attention to Maria instead of her. As a result, when Lucifer makes a short trip to take her mind off her defeat against Belial for a while, Leviathan begins to sexually torment the forlorn girl; but when Maria eventually admits that she has herself sometimes felt envious of her friend Mina because she had not found anyone to love in her life, and states that envy born of love is not a sin, she manages to stir doubts in Leviathan and break the demon's hold on her.