Uncanny X-Men (2015) #17

The X-MEN have waged war on the INHUMANS! But as the X-Men fight for their future, one X-Man fights for her humanity. Driven mad by the influence of her vampiric brother, M desperately tries to stop herself from feeding on the marrow of her enemiesand her friends! Will she succeed? Or will she add to the body count? Rated T+