Katerea Leviathan was one of the three leaders of the Old Satan Faction in the animation series High School DxD. She was a descendant of the original Leviathan.
Katerea was a tall bespectacled woman with a voluptuous figure. She had tan skin with long brown hair tied into a bun with a headset and she had purple eyes (blue-grey in anime).
She wore an extremely low-cut dress and it had a high slit which exposed a large portion of her breasts
Katerea hated the current Satans, believing that they were defiling the name of Satan itself. Furthermore, she wished to cause destruction and chaos to the world to rebuild it into a new world under the rule of herself and the other descendants of the original Satans with the administration meant to create a new world where the system, laws and doctrine suit the ideology of the Old Satan Faction. She is also a brutal, twisted, highly sadistic, and extremely cruel and ruthless pervert.
She and the other descendants of the original Satans (except Vali) believed that the current Devil system was mistaken and sought to change it by killing the current Satans and taking control of the Underworld.
Birth of the Breast Dragon Emperor
She appeared in Volume 4 during the meeting of the Three Factions, attempting to kill both Sirzechs Lucifer and Serafall Leviathan but fought against Azazel instead after the latter made fun of her. While both sides were equally matched in the initial stages of the fight (due to Katerea absorbing Ophis' snake), the battle is overturned by the sudden betrayal of Vali Lucifer. Despite this, she was still defeated by Azazel who revealed his Artificial Sacred Gear. In a final act of desperation, she converted her arm into indestructible tentacles and activated a powerful self-destruction magic spell, to which Azazel responds by cutting off his hand, telling her "I'll give you a hand, at least". He then stabbed Katerea with a light spear, effectively killing her