Maris is a thief. A common, low down, swarmy thief. It’s not her fault she’s that way, though. She’s nice, has a sweet personality, and is most likely to talk a person into giving ‘the poor, suffering little me’ their money, due to her limited skills as a pickpoket.
What she is skilled at, however, is very, very strange for a theif. She likes reading, and has collected many old manuscripts, and is sometimes saught out for just knowledge.
Animals have parasites and diseases, so do plants, there are even bacteria that cann dissolve oil spills or plastic or what have you - why couldn't there be a disease living off magic - a magic item could be infected, losing power and speading the plague to other equipment it contacts, while a magic user would slowly lose his powers and contaminate all he works with or casts a spell at...