Seth is sort of like
Abel's little sister, and the empress of the Empire. She looks small and frail but she's very fast and especially dangerous...
so don't get her angry!
She helps Ion and Esther a couple of times without revealing who she really is.
She's happy to see that Abel is there, but that smile is quickly wiped away as Seth tells her that Cain is back and he's trying to destroy the peace between the Empire and the Vatican to cause an all out war between Methuselah
(vampires) and humans.