While the full extent of her personality has yet to be revealed, Leviathan's two heads appear to have independent personalities. The right head is more cynical and more in charge, while the left head appears to be relaxed and composed. The left head was even friendly to Mammon, unlike the right, and got mad when the right head moved them away from him. The relationship of the two heads is further indicated when Mammon invited Leviathan out after Blitzo's trial; the right head showed active annoyance at Mammon and attempted to ignore him, but her left head seemed to genuinely enjoy being around him, and looked hopefully at the right head, indicating that she hoped that she would allow them to take up Mammon's offer. It is unknown if she shares the same views of superiority as the other deadly sins do. However, she does recognize Satan as her leader and "the law" of Hell.
Speaks in slow, rolling clauses; uses maritime metaphors and calm gravity.
