A sketch of my heroine Eider from my first book.
Writing a protagonist who's a double amputee was tricky by itself, but there was an added challenge in that part of her story is based on the fairy tale "The Girl Without Hands."
(The book is based on a number of fairy tales, including "Sleeping Beauty", "Beauty and the Beast", "Cupid and Psyche", "East of the Sun and West of the Moon", all set in an original narrative.)
In some ways, doing a fairy tale retelling can make your job as a writer easier because the broad outline of your story is already in your hands. But it presents a lot of challenges just by virtue of what it is. One of the biggest questions -- how far from your source do you deviate?
On one hand, you want your version to be recognizable as the fairy tale -- you want to respect these traditional tropes and tensions and draw interesting material out of them. On the other, if you're just doing a point-by-point retelling, what exactly are you bringing to the table? Is there any new, original energy to your story, or is it just old and tired? What's a useful change or subversion, and what's just a gimmick?
"The Girl Without Hands" has the advantage of being less well known, so in that I wasn't worried about it feeling old and tired. But it has some difficult tropes, both in how questionable they are (she marries a king who clearly thinks badly of her; her hands are magically returned to her) and just in how... odd and difficult they are to get your head around (her main antagonist is literally the Devil).
I had definite opinions about how I wanted to tell Eider's story, places I wanted to deviate, and I gave the ending (does she fall in love? does she regain her hands?) a lot of thought. I think some readers might not agree with me, but I'm happy with the choices I made.