In The magic Thief by Sarah Prineas, “Conn should have dropped dead the day he picked Nevery's pocket and touched the wizard's locus magicalicus, a stone used to focus magic and work spells. But for some reason he did not.”
The Thief by Megan Whalen Turner enrolls the help of a skillful thief to get to a treasure.
The list is so long, it has almost become a fantasy subgenre. Maybe the more represented thieves and cutthroats are pirates. Think Peter Pan, Magic Marks the Spot, The Vampirates and Piratica Series. Tweenagers love pirates because they are funny scoundrels. No character charms more a 10-year old than the bloodthirsty pirate. Their getups include every item kids dream of, from fun weaponry, eye patches, hooks to the muskets and sabers and old army long coats. They bury treasures, outwit their enemies and like a good battle as well as a good laugh. They are superstitious and cunning. They like to travel, mix cultures and they add spice to everything like their language or the way they treat their prisoners. Pirates are fascinating for tweenagers because they allow the kids to play with language and it allows them to get away with everything, at least virtually.
Thieves or street urchins are liked by tweenagers because they are usually independent and witty. They are usually good kids who have learned to survive. They attract our sympathy. Kids that age love tricking their parents and friends, secret codes and playing pranks. They love keeping secrets even if they are very bad at keeping them. For this reason, they like magic tricks and magic in general. No wonder they can root for children thieves. However, pirates and thieves have been so much done, it is hard to make them fresh. They have their own subculture which distinguish them from other characters and if you try to describe pirates or thieves any other way, your reader will not take you seriously. They have their own codes and language and community structure.
I can see one big reason why a writer would write about thieves and pirates. Writers are attracted by these characters because it is easy to draw dear consequences from their acts. Stealing will get you in trouble even without trying and living among pirates will get you into situations you will have to fend for your life. Choosing to write those characters makes a plot come to life naturally, without much effort.
Write about pirates who travel through time and have to change a few habits on the way to survive, although a pirate who is not allowed to kill or battle will lose his charms. So make your pirates still intimidating and make them steal, but change all the rest about them.
Your character could be one member of the pirate ship nobody pays attention to like the cook. Your thief could steal without wanting to.
Your character could mistakenly be taken for a thief and would have to go after the real thief to save himself.
Make pirates and thieves part of a subplot.
“Pirates: Fantasy’s Forgotten Scoundrels.” Fantasy faction. August 27, 2012.