One knight, known as the Sacrifice, is chosen each generation to journey to the heart of the Dark Citadel and battle the Deathless God King. None ever survives. But in sacrificing a young man each generation to be cut down by the Infinity Blade, the simple farmers of the Citadel’s neighboring villages are spared the God King’s wrath.

And so it goes, for generation after generation, until Siris, another member of the sacrificial bloodline, manages to slay the God King and claim the Infinity Blade as his own.

After killing the God King, Siris finds the Infinity Blade to be more than a sword. It’s a key as well, one that opens a secret passage to a dungeon in the Dark Citadel. After fighting three immortal Deathless imprisoned in the dungeon, Siris unlocks another hidden room. This one filled with inanimate God King bodies floating inside tanks.

Ultimately, Siris is lead into battle against a mechanized warrior, Zero, whom he defeats. But with his dying breath, Zero warns Siris that someone will come looking for the Infinity Blade.

Having defeated the God King, Siris returns to his home. But the elders of Drem’s Maw ask him to leave, fearing that other Deathless will come seeking either the Blade or revenge. Hoping to find answers about the Deathless and what they may want, Siris returns to the Dark Citadel at Lantimore, only to learn that the God King may not actually be dead.

At the Citadel, he encounters an assassin named Isa. At first adversaries, Isa eventually offers to help Siris on his quest to find the location of the Worker of Secrets, who created the Infinity Blade. Not knowing where the Worker is imprisoned, the two travel to another Deathless, Saydhi, who has an outstanding offer to answer any request for a warrior capable of defeating her minions. 

Siris does just that and, true to her word, Saydhi reveals the location of the Worker of Secrets. Saydhi then attacks Siris, forcing him to kill her. Believing he has found another lock for the Infinity Blade to act as key, Siris places the Infinity Blade into a stone pillar. But it’s a trap. The God King reveals himself, takes the Blade, and is about to kill Siris. Isa beats the God King to it, firing a crossbow bolt that kills Siris.

Siris awakens in a rebirth chamber and realizes the truth – that he is in fact a Deathless. He remembers now that he was known long ago as Ausar. The generational Sacrifice of his village has always been Ausar, reborn again and again. His deaths have slowly been powering up the Infinity Blade until it reached a point where it could permanently kill any Deathless it struck. The death of Saydhi was the final charge the Blade needed to reach its full potency. Had the God King used the Infinity Blade to slay Siris, he would have been permanently dead. Since Isa killed him, Siris was able to be resurrected once more.

The God King-slayer, Siris, having learned that he is in fact a Deathless who used to be known as Ausar, embarks on a quest to find the Worker of Secrets. The Worker created the Infinity Blade as a weapon that could kill the Deathless and Siris wants to fully understand how the Blade works and its true purpose. Siris’ partner, Isa, is shaken by the realization that the man she followed on a quest to rid the world of Deathless is himself immortal, and leaves to forge her own destiny.

Siris heads to Saranthia to find the Vault of Tears, where the Worker of Secrets is imprisoned. There he meets Thane, High Lord of the House Ix. Upon defeating Thane, Siris unlocks a seal, but dies in the process. Fortunately, a mechanical helper named Tel revives Siris in a Phoenix Chamber.

Again and again, Siris returns to Saranthia. He defeats three Blood Sentinels, each of whom guards a seal that unlocks the way to the Worker of Secrets. Siris sacrifices himself each time he unlocks a seal, but is always reborn.

With the Vault finally unsealed, Siris meets the Worker of Secrets, only to learn that another Deathless must take the Worker’s place if he’s to be freed. Siris hunts down and captures the God King, whose real name is Raidriar.

Bringing Raidriar to the Vault of Tears, Siris is ready to finally learn the mystery of the Infinity Blade, but the Worker has other ideas. He betrays Siris and locks him in the Vault of Tears with Raidriar. It’s revealed the Ausar was the one who originally imprisoned the Worker, who now has his revenge.

With the God King and Siris imprisoned together and the Worker free, Isa arrives at Vault of Tears. Presumably she’s there to free Siris

Long months have passed since Siris and the God King, enemies betrayed, together, were left to rot in the prison at the Vault of Tears. Their true enemy—the Worker of Secrets, creator of the Infinity Blade itself—now reigns.

Upon finally obtaining freedom, Siris must unravel plots that seem to make no sense, lead a rebellion with no direction, and fight against the division within his very heart.  The secrets unraveled will dig backward in time toward the origins of the Deathless and the true nature of the world itself…

The epic conclusion to the Infinity Blade saga! Siris and Isa have joined with the God-King Raidriar in a desperate attempt to destroy the Worker of Secrets and his army of Deathless titans and warriors.