“Many years before, Abacus had come to the conclusion that the greatest of heroic stories have the shape of a diamond on its side. Beginning at a fine point, the life of the hero expands outward through youth as he begins to establish his strengths and fallibilities, his friendships and enmities. Proceeding into the world, he pursues exploits in grand company, accumulating honors and accolades. But at some untold moment, the two rays that define the outer limits of this widening world of hale companions and worthy adventures simultaneously turn a corner and begin to converge. The terrain our hero travels, the cast of characters he meets, the sense of purpose that has long propelled him forward all begin to narrow—to narrow toward that fixed and inexorable point that defines his fate. Take the tale of Achilles. In hopes of making her son invincible, the Nereid Thetis holds her newborn boy by the ankle and dips him into the river Styx. From that finite moment”