The Deathless are a biologically-engineered immortal species that inhabit the world of Infinity Blade. A Deathless can be physically humanoid, like Siris, or a different creature, like Gortoel. Deathless individuals possess the ability to transfer their QIPs, or souls, into new bodies when they die. Some Deathless are known to maintain Rebirth Chambers where they can be reborn after death. However, three ways to kill Deathless permanently have been revealed, such as a fatal strike from the activated Infinity Blade, "QIP destabilization", an example of which is shown by the Worker of Secrets in Infinity Blade II, or destroying every available body and Rebirth Chamber, as the Worker of Secrets explains to Raidriar in the beginning of Infinity Blade III.
Not much is known about the history of the Deathless, though it is evident through the use of holographic projectors and "deadmind" computer systems that the Deathless come from a time and place with very advanced technology. In Infinity Blade: Awakening, it is noted that, thousands of years ago, the Deathless used "armor that worked like a machine". The Deathless now use simpler armor so that battles are based on skill rather than technology.
In Infinity Blade: Redemption, it is revealed that Galath did in fact create the Deathless from employees in his multilevel company. He uses biological engineering to modify their QIPs and bodies, as shown as when he turns Uriel's son Jori, currently known as Raidriar, into a Deathless.
Deathless individuals do not age, possess greatly enhanced healing capabilities and physical attributes, and can survive without typically life-sustaining air, water, or food. They do, however, need to excrete waste if they consume, as shown in Infinity Blade: Awakening, when Siris finds the silver toilet of the God King. The only confirmed ways of killing Deathless are through the use of the activated Infinity Weapons, Q.I.P. destabilization, which has only been demonstrated by the Worker of Secrets so far, or killing them and denying them a body to return to.
Despite the supported claim that Deathless do not age, it is stated in Infinity Blade: Awakening that Ausar was reborn into a child's body multiple times, eventually to reach manhood and fighting the God King. It is also stated by TEL that Ausar once grew old and had children, one of which was Archarin. Either this is an inconsistency in the novel, the Deathless must take extra unmentioned measures to avoid aging, or it is possible that TEL could cause Ausar to age to a point.
It seems that Deathless individuals possess greatly enhanced agility and prowess. One ability unique to Deathless is the practice of "the Patterns of True Swordsmanship", designed to eliminate multiple opponents in a short amount of time. In Infinity Blade I and II, Raidriar can be seen leaping great distances. Also, Siris can safely drop from the bridge leading to the Stone Demon, a height that would kill or severely disable a normal human, and in Infinity Blade III, he was dropped by Ba'el from a few hundred meters high, and not only survived, but was able to still attack her.
It is known that a mortal can become Deathless, though it is not known if all Deathless were once mortals. The child of a Deathless can steal his or her parents' immortality, which makes many Deathless wary of reproduction. The God King himself was once a mortal known as Jori, until he died and his father, Uriel, pleaded with Galath to save him. Galath complied, thus transforming him into a Deathless.
- Siris or Ausar: The main protagonist of the series and the player's character. He was known as "Ausar the Vile" in his previous lives. Ausar's memory was wiped by the Worker of Secrets when he used the Redeemer, making him unaware of his state as a Deathless. He now aims to free the world from the grip of other Deathless. In Infinity Blade II, he is imprisoned with Raidriar in the Vault of Tears for two years. He and Raidriar were released from the prison by Isa.
- Isa: A protagonist of the series, whom Siris met in Infinity Blade: Awakening. In Infinity Blade II, she saves Siris from being killed permanently by Raidriar with the Infinity Blade by shooting him in the head with an crossbow bolt. After Siris is imprisoned in the Vault of Tears, she spreads stories of Siris to create a rebellion against Galath. She frees Siris, and Raidriar unintentionally, from the Vault of Tears. In Infinity Blade: Redemption, she was made a Deathless through the use of a Pillar of Sanctification.
- Raidriar the God King: The main antagonist of Infinity Blade I and II, encountered as the final boss of both games. He is also known as the God King because he ruled a vast empire of unknown size and deceived his subjects into taking him for divinity. In Infinity Blade II, he is trapped with Siris in the Vault of Tears. He managed to escape by slitting his throat when Isa opened the Vault, but was killed permanently by the Worker of Secrets in the prologue of Infinity Blade III.
- Galath the Worker of Secrets: The creator of the Infinity Blade and the Deathless species. He is the main antagonist and final boss of Infinity Blade III. He has profound knowledge of the Deathless and their technology. He was trapped in the Vault of Tears by Ausar the Vile, but he tricked Siris into taking his place there. In Infinity Blade III, he was confronted by Radriar in his stronghold. He asked Raidriar to join him, but ended up killing Raidriar after Raidriar transported Galath's datapod, filled with his plans and mysteries, to his own stronghold at Larioth.
- Thane: A Deathless featured in Infinity Blade II who resides at the top of the Tower. He claims to uphold the Great Pact by guarding the Vault of Tears. Thane is the High Lord of House Ix, one of the four Deathless Houses. He tried to disarm Siris and to stop him from releasing the Worker. He was permanently killed when The Worker interfered in battle by destablizing his Quantum Identity Pattern. In Infinity Blade III, Thane reappears as a QIP Abomination. This is a failed attempt by the Worker to utilize remnants of Thane's QIP and create a Soulless copy of Thane, turning him into a monster.
- Saydhi: A Deathless information dealer in Infinity Blade II, encountered in her estate. She was permanently killed by Siris using the activated Infinity Blade after she told him the location of the Vault of Tears.
- Ryth: A powerful Deathless Blademaster found in the Hangar Bay of the Tower in Infinity Blade II, Raidriar's Stronghold and inside the Worker's lair in Infinity Blade III.
- Ashimar: A Deathless who was once the friend of Raidriar known as Jarred. He duels Raidriar in the Worker's stronghold and is killed permanently by the Infinity Blade.
- Therin the Killer of Dreams: A Deathless found in the coliseum north of Raidriar's palace, also known as the Killer of Dreams. He is known to be antagonistic to Raidriar's Pantheon. He appears in Infinity Blade III and wields The Infinity Spear.
- Lelindre: A Deathless, known as the Mistress of the End, who refused Galath's plan for salvation and stayed behind to burn. She appears in Infinity Blade III and wields The Infinity Daggers.
- Oslim: A Deathless, known as the Deathless Bloodmage, who was ordered by the Worker to slay Siris/Isa. He appears in Infinity Blade III and wields The Infinity Swords.
- Minnoch: A Lesser Deathless found attempting to conquer Raidriar's domain, specifically Drem's Maw. He is killed by Isa, though it is unknown if it is permanently.
- Zuorsara: A Deathless High Priest of a cult dedicated to resurrecting Ausar. He is found in the resurrection chamber beneath the statue at the Plains of Koroth. He is killed shortly thereafter by Isa. His current status is unknown.
- The Collector: A Deathless Blademaster said to be hunting rare and ancient weapons.
- Terrovax, the High Lord of House Burke: He confronts Isa in the Seccian Desert. After she defeats him, he divulges the locations of The Infinity Weapons.
- Melek, the Warlord of House Ix: Having known Ausar in his past life, Melek offers Siris a chance to become Ausar again, to which Siris refuses. He is killed in the ensuing fight.
- Ealoseum: A golden-armored Deathless located in the Temple of Lantimor dungeon.
- Kuero: A hooded Deathless located in the dungeon.
- Gortoel: A troll-like Deathless located in the dungeon. He was Galath's bodyguard when Galath was an inventor.
- In Infinity Blade III: Kingdom Come, some sort of very advanced colony can be seen on the Moon. This may have been where Galath and the Deathless stayed while they destroyed the world.
- It is unsure what classifies a Lesser Deathless and a full-fledged one, whether it be territory, power, slaves, or the Q.I.P. itself. It was revealed that "lesser Deathless do not have the power, wealth, or influence to acquire and maintain their own secret caches of buds. This makes them much more vulnerable to the manipulations, plotting, and scheming of the other Deathless."
- Sanderson, Brandon. Infinity Blade: Awakening. 1st edition. Salt Lake City, Utah: Chair Entertainment Group, LLC, 2011. eBook.