Carmilla mentioned!!! Lesbian vampires huzzah!!!!!
Though it's ironic that she raised Carmilla as a counterpoint, because despite being the OG lesbian vampire in commercial fiction, the titular vampiress did not have a kin the way Count Dracula did. She just approached young girls, seduced them, and then ate them slowly over time. The bloodlinking ritual only happened in Dracula, and Count Dracula pretty much fumbled it by dying before Mina Harker's transformation was complete.
In other words, she namedropped Carmilla not because of the kinship topic—she's saying that she knew Ruruna was a lesbian vampire.