In V.E. Schwab's Shades of Magic series (2017), the protagonist is named Kell Maresh.
I just recently finished reading the Mistborn: The Final Empire (2006), by Brandon Sanderson. In this book, two of the most important characters are brothers named Kelsier (who goes by the nickname Kell) and Marsh.
This seems unlikely to be a coincidence. Has V.E. Schwab admitted to being a Brandon Sanderson fan, or otherwise discussed the origins of Kell's name?