SunlightLurker

If you’re going for soap opera vampire then there’s Barnabas Collins. I think it was last year during Halloween week Shortland Street had a patient who thought he was a vampire and tried to bite nurse Madonna Diaz. Not the weirdest patient, or staff member, the hospital has had. That is a possible angle, someone who believes they are or someone else is a vampire. It’d take some contrivances, but contrivances aren’t anything new and some storylines have run entirely on them. A Halloween party would be a less intrusive way to do it.

Looking at the family units and their known relatives present at the moment, maybe none that could plausibly have teenagers unless a teenage relative arrives, there's an adoption or a surprise teenage relative turns up. The closest thing in the last couple of years is Ava (teenage relative arrives), and we've seen how that's played out.