VEELAS!
Veelas are humans and the line continues only through parents. So you need to have to have Veela blood in the family if you want to be one. Veela's are born not turned. Veelas tend to be usually females but there have been few males too, so the line could be kept pure or going on.
Appearance:
Veelas usually have white-gold or then blonde hair, their eye colour various but most of the times it’s blue. Their skin colour is usually white. They appear as human for most of the times. If Veela gets angry then they can transform into harpies - their faces turn into cruel-beaked bird heads while long scaly wings burst from their shoulders. That’s basically only main difference from humans on looks and it doesn't happen all the time when they are angry, so don't make it come always out.
Abilities/Strengths:
Veelas can throw fireballs from their hands. They don’t do it very much, most of the times it happens when they are angry. And they don’t need a wand for it.
Also you could say her charming way to males mostly is their ability. They can make males to do things what they like and also all males seem like they have fallen for that current female Veela, who is doing the charming spell on them. (Of course, they can attract females too if they are into them. Also, males could pose such powers)
When Veela is young her abilities aren’t strong for sure, she can’t make fire big fireballs or she can’t charm someone for a long time. When they grow up their abilities will be stronger for sure. They can make bigger fireballs and also can charm someone for a longer time.
Mostly the ability of fireballs seems to be only when you are pure-Veela. There isn’t much known about Half-Veela having this ability, just no one hasn't seen anyone doing it who was Half-Veela.
Also if you have less Veela blood in your Charming skills aren’t very strong. So you can’t make your Eight-Veela charm many people same time, well your Veela probably could manage to charm mostly only two-four people same time. Make it seem like it’s logical.
Weaknesses:
You could say their weaknesses is that they are mortal like humans and they can be killed same way as humans. Bullets, swords and so on hurt them same badly as humans.
Purity of veelas:
Pure-Veela – They are usually the ones who have started the line.
Half-Veela – Is someone whose one parent is pure Veela but other is wizard/muggle etc and doesn’t have Veela blood in.
Quarter-Veela – Is someone whose one parent is half Veela and other is same who has no Veela Blood.
Eight-Veela – Is someone whose one parent is Quarter Veela and other is same who has no Veela Blood.
What happens really after Eight-Veela isn’t know. Probably the line dies down.