Okay, so Karla has Craft. She wears the Sapphire, which means she's pretty powerful, as that's the fifth strongest Jewel (out of thirteen). If she goes through the Offering while at school, she'll come away with the Ebon-Gray, which is the second strongest. The magic she creates will be very powerful and she'll be able to create a lot of magic before running out of energy.
Re: Magic abilities
Okay, so Karla has Craft. She wears the Sapphire, which means she's pretty powerful, as that's the fifth strongest Jewel (out of thirteen). If she goes through the Offering while at school, she'll come away with the Ebon-Gray, which is the second strongest. The magic she creates will be very powerful and she'll be able to create a lot of magic before running out of energy.
Basic Craft abilities are listed here
In addition to all that stuff, she belongs to three castes: Healer, Black Widow, and Queen. Caste-abilities are listed here
Basically, she's really strong and really versatile.