Well all the horrific meta flags aside...
This chapter was pretty messy and all over the place. I know introduction chapters are often a bit rushed or try to establish as many things as possible for the sake of garnering interest, but sheesh. We jumped around way too much and made it really confusing.
The plot of finding whatever the key leads to was instantly abandoned after vampire girl attacked the random dude and then sucked protag's blood for no reason. Maybe the implication is that she worked up a sweat and got thirsty and couldn't resist.... and then they both got really weak and went to sleep. Still messy.
To a vampire there might not be much of a difference between a 14 year old or a 40 year old, but to me that kinda matters. She is a bit young for this, so I hope it doesn't go too far (those comments about the lolicon hentai garbage don't help).
Cautiously curiously continuing to follow this series.