Does that work for vampires too? As for Liches, I thought the common myth about them is about wizards seeking immortality by becoming skeleton monsters, it doesn't make sense for a Lich to be a slave.
See that's where things start getting kind of...strange.
You remember how I said that the Lamia's were the proto-Vampire/Succubi? That's what stops the Vampires and Succubi from falling into the Undead category. They're essentially a sub-species that evolved from the Lamias thanks to specific changes in their environment.
When humans started to take over and replace the vegetation with man made structures, Lamia's started to die in rather large droves. Moving along a paved/dirt road can be hell on your underbelly since the Lamia's didn't have any scales their to protect their soft spots. Thus, running from humans became rather difficult when the very act of running hurt you. Top that off with the fact that during the early stages of evolution Lamia's couldn't hide their animal halves, then add in that humans were starting to create ranged weapons like bows and arrows, and you have a lot of dead Lamia's.
So, as time went on the Lamia's that survived realized that if they were to keep living in a world where humans are dominant, they would have to blend in with the humans or at least not make themselves so obvious with their giant animal halves. So, with a little help from magic, they were able to find a way to hide their bottom halves at will. Most Lamia's decided to just keep their animal halves under wraps until they needed to feed.
Others, however, completely abandoned their snake halves. They didn't hide them, they
replaced them.
Basically, Lamia's are blood sucking seducers that have the lower half of an animal.
A Vampire is a blood sucking seducer, with no animal half. They tend to lose the maneuverability and other advantages of having an animal lower half (four legs run faster than two), but gain other advantages.
As for Liches and other Undead, they aren't necessarily slaves.
Really, it all comes down to who it is that brings them back.
A lot of the time it's more like a business partnership.
"What? Thought I was gonna die there."
"You were, then I brought you back to life. Wanna become my minion?"
"No."
"Ok. Have fun being Undead."
As for the Immortality thing, that's something that doesn't exist at all.
With Belief being as powerful as it is, saying something is "immortal" is the same as saying "no one's taking great pains to kill it yet."
Also, wasn't Ana supposed to gain more actions according to her speech,
Not more Actions, just more things she can do.