1810 England, the height of the Napoleonic wars. It was thought that humans walked the path of enlightenment leaving monsters and dark things behind. However, those monsters and night stalkers merely hide in the darkness, as a young maid, Bernadette, soon finds out.
What Philip said! Jacques is just being a punk and showing off while Jinny struggles simply to get near him.
I don't expect peeps to know this, but sometimes I use this fun visual trope in my other comics too, and certainly not only on vampire characters. It's meant to be a silly thing partially inspired the innocent but endearing sparkles of the Armstrong family, from Fullmetal alchemist.