Infinity Blade Redemption, which follows the story shortly after it ended in the novella Infinity Blade Awakening. There we met Siris, a young warrior who had been trained by his people with the single purpose to battle the oppressive God King and to die in that battle against the immortal being. However, the battle ensued and, confoundingly, Siris did not die. In fact, he seemed to have slayed the God King. Ultimately, Siris understood that the God King was truly immortal. When he body shell was destroyed, he simply regenerated into a spare shell. Siris, who had been bred to despise the God King and all of the deathless souls of the land, soon comes to understand through his companion Ida, who had tried to kill him several times in the past and actually succeeded once, that he too is one of the deathless. However, he seems to be of a different ilk. A deathless with a conscience and a cause.
Alternated with this story arc, we come to understand a bit about the origins of the world of the Infinity Blade. How it was created by a megalomanical madman, a technological genius who wiped away most of humanity for no other reason but to get his kicks. To play God and savor the sweet taste of absolute control. Creation and destruction completely at his whim. Ultimately we see a strange and unlikely alliance between Siris and the God King as they are forced to join forces to stop the truly all-powerful being called The Worker. Along the way, he who was once the hero and defender now becomes the scourge and he who was the scourge becomes the hero and defender. Ultimately we see a lost soul who finds redemption. A great narrative that was left ripe for future development. Sanderson states in the acknowledgements that he looks forward to further development of this world.