Based on the vampire from the novella Carmilla, she a beautiful, dangerous, and unbelievably powerful vampire who can copy the powers of others by drinking their blood. She can't be killed by any known means even the Gods or other divine beings can't.
She is the first of a different race of vampire than the one shown in American Vampire.
Carmilla like the one from the book is mainly attracted to women and is in love with Wonder Woman who actually does develop a desire for Carmilla. Carmilla's goal is the enslavement of humanity with Diana as her consort.
It is hinting more likely that Lois did it to protect Superman. I am still thinking that Lois did it because she felt that the world needed a Superman thus with him Super flaring his powers she felt the world was endanger.