I really like this. It's short, concise, and it sounds intriguing. :)
I like this too. You really summed it up quite nice in a few words. I wonder though.. "must kill" or should it be "forced to". Just curious. Good job!!
This is simple, reads well and sets up character and conflict nicely. I wouldn't change it, but if you were ever expanding for say a query letter, you could put an intriguing inciting incident before 'a teen witch' and do away with 'torn between' because you show that in the second part of the sentence anyway.
It reads quick and gains my interest immedetly.
I like this, too. But the parallels seemed slightly off: love = beloved protector and duty = destroyed by a shadow demon? Is there a way to keep it this beautifully concise and hint at her duty also?? Just a thought.