Martyrdom: the Colouring Book by Hallie Fryd, illustrated by Julia Gfrörer. To wit:
The lives of the saints are filled with inspiring, life-changing moments—but the deaths of the martyrs are where you’ll find the real “Oh, hell no!” moments of history. This adult (very adult, as the body count will quickly indicate) coloring book gives aspiring crayon and paper artists the chance to hone their craft while also buffing up their knowledge of Catholic history