From what has been revealed, Seviathan and Charlie used to date. They were at least dating around the time of hell school.
Helsa is Seviathan's sister. According to Faustisse, the two have a neutral siblings relationship with each other. While Helsa and Seviathan don't hate each other, they just don't appreciate each other. They are so busy with their own stuff that they don't care about the other. And given that Helsa and Charlie share an antagonistic relationship, it is unknown if Seviathan's romance with Charlie affected his and Helsa's sibling relationship.
- Charlie having an ex-boyfriend was first mentioned in Vivziepop's twitter. Pictures of Seviathan and his family can be seen with the Magne Family all over the hotel as the two families are of elite standing.
- Sevianthan's name is a reference to Leviathan, a creature which takes the form of a sea serpent in the Hebrew Bible in the Book of Job, with "S" replacing the "L".
- Before the official name was announced, fans referred to him as Harold von Eldritch.
- He is described as a "big jerk chad" kind of evil because he is ignorant.
|Main characters||Hazbin Hotel||Charlie • Vaggie • Angel Dust • Alastor • Husk • Niffty|
|Helluva Boss||Blitzo • Millie • Moxxie • Loona • Stolas|
|Overlords||Alastor • Rosie • Valentino • Velvet • Vox|
|Supporting characters||Baxter • Cherri Bomb • Crymini • The Egg Bois • Exorcists • Helsa • Katie Killjoy • Lilith • Lucifer • Mimzy • Razzle and Dazzle • Seviathan • Sir Pentious • Tom Trench • Travis|
|Others||Arackniss • Barbie Wire • Collin • Eddie • Fat Nuggets • Fizzarolli • Robo Fizz • Henroin • Loo Loo • Martha • Mrs. Mayberry • Molly • Octavia • Ralphie • Roo • Stella • Tilla • Villa • Wally Wackford|