What is a Queen Vampire doing in my fortress?

This is the first time my fortress was promoted to Mountainhome before flooding with water, lava or HFS, so I don't know if this is expected. I got a message that the King had arrived with his entourage. Checking the Nobles screen, I see:

Dodók Kûbukthabum, queen vampire
...
One Hundred Ninety-Six Kills
Eighty-eight dwarves in Scorchedtraded
Ninety-four dwarves in Scorchedtraded
... When possible, she prefers to consume giant jackal.
... She has a shortage of patience.

Should I worry? If she was a real vampire, she wouldn't be bragging about it and put "Vampire" in her title, right? If she is a vampire and I kill her, will I get a new king/queen?

Edit: Also, she has the scary Ñ symbol but is still friendly. So I suppose she's a normal vampire-turned-politician?

You won't get a replacement ruler if your current one meets an (un)timely end. She sounds like a real vampire. Confining her to a blocked-off area filled with migrants sounds like the best solution. Or you could make a queen zoo with a crystal clear glass enclosure in the middle of your grand dining room. Drop in some critters and miscreants and enjoy the spectacle.

It may have been discovered that she's a vampire after she'd become the queen, so she couldn't be chased out.

This isn't particularly exotic, people get elf and human kings often enough (and you can't become an elf or a human if you're a dwarf, unlike with vampires), though this situation certainly has more fun potential.