Leviathan is a very loyal parasite to Squigly through and through as well as honorable. He has shown guilt whenever he felt like he put Squigly in a dangerous situation. He is said to be a gentleman, but sometimes, he has a dry wit when talking to his opponents. He also has a feral side since one of his attacks has him biting his opponents multlple times while dragging Squigly along. He is also shown to speak in an English accent.
- Leviathan's name comes from the Judeo-Christian demonic sea monster of the same name that is one of Lucifer's minions. In demonology, the Leviathan is associated with the sin of Envy. Leviathan himself quotes the Christian bible.
- Leviathan was present for the clash between Samson's old host, Delilah, and Eliza.
- Leviathan was attached to Roberto's arm/shoulder area and was visible externally.
- Leviathan goes through Squigly's right ear and out of a hole on the left side of her head. This suggests that the hole on the left side of her head is the bullet hole caused by Black Dahlia at the time of Squigly's murder. This is contradicted however in the illustration depicting Black Dahlia shooting her on what appears to by the right side of her head, not the left.
- Skullgirls Art Director Alex Ahad drew a non-canon human version of Leviathan by fan request. The design features Leviathan as a lithe man with slicked, spiked hair and two large horns growing out backwards from his temples while wearing a suit and tie.
- He seems to bear ill-will against the Renoirs. This may be because the Renoir family made attempts to "stamp out the songs, stories, and traditions of the Meridian Kingdom" which included the Contiello's opera singing. He also refers to them as "usurpers" on multiple occasions, though the exact reason for this is unclear.