When it comes to resistance in the mutant world, Marrow is an obvious character to include. Raised underground with the Morlocks, Marrow can manipulate her bones and even use them as offensive tools in a fight. Not only can she control the shape of her bones, but she can even change their density and toughness to make them more deadly. In addition to that, she has an increased healing factor that protects her whenever she uses her abilities.
It would be interesting to see mutants and Morlocks fight for respect side-by-side in The Gifted. Morlocks are groups of mutants who were considered outcasts even from the rest of the traditional mutant community due to their appearance or rather extreme abilities. Marrow or someone in her family could start a relationship with a normal mutant to strike up some type of Romeo-Juliet deal and get the two antagonistic groups to eventually come together.