Titans (also known as The Ancients) are mighty beasts of Hell, far larger than regular classes of demons. They serve as beasts of burden for the more powerful demonic entities, and as giant combatants in the armies of Hell.
During the war between the Night Sentinels and Hell's forces, Titans appear to have been Hell's counter to the Sentinel Atlans, though they do not seem to have fared particularly well against them. Titans do not seem to have been deployed to Earth on the same scale as they were deployed to Argent D'Nur, seemingly only used in a rear-echelon role to transport the great temples of the Hell Priests.
Titans are implied to be enormously difficult to kill, even by demon standards - they can have immense portions of flesh and organs blown off of their bodies with no loss of vigor. Only Atlan weaponry or the hellish blade of a Crucible are effective at putting them down for good, and even the latter is not a permanent solution; according to Samuel Hayden, a Titan stabbed by a Crucible will be revived as soon as the blade is removed from its body.
The invasion of Taras Nabad was spearheaded by a particularly powerful Titan known as The Dreadnought, which proved impossible for the armies of the Argenta to defeat until the Seraphim empowered the Doom Slayer through use of the Divinity Machine of the Maykrs. Thus empowered, the Slayer cut down the Dreadnought with his Crucible, leaving the blade planted in the creature's heart.
A single Titan only known as "The Titan" faced the Doom Slayer as he rampaged through Hell. Despite being especially large and powerful even for a Titan, it proved no match for the Slayer; the precise manner in which he defeated the beast is unclear, but its skeletal remains are strewn across the area of Hell's Great Steppe.
Living Titans are present in the Hell city of Nekravol; one is chained in a pit of lava outside the demonic city's gates with streams of molten material pouring from its eyes, and two more are present at the highest level, pulling on chains to hold a section of the Maykr energy transfer device in place.
Another unique Titan, the Icon of Sin, was birthed from the torture of the son of the Betrayer and controlled using his heart. Later, the beast was transported to Urdak and modified with Maykr technology to allow the Khan Maykr influence over it, but the Slayer destroyed the heart and left the beast to its own savage instincts, ultimately planting a Crucible blade in its exposed brain and ending the demonic assault on Earth.
In The Ancient Gods - Part One, a dormant Titan named Maligog is found in the Blood Swamps of Hell, which the Doom Slayer must awaken in order to reach Ingmore's Sanctum, where The Father's life sphere is being held. After assembling the seal and defeating the Trial of Maligog, the Slayer awakens the Titan, allowing it to carry him to the peak of the mountain where the Sanctum lies.
In The Ancient Gods - Part Two, there are a few Titans present among the horde of demons summoned by the Dark Lord to defend Immora from the Doom Slayer. When the Night Sentinels come to the Slayer's aid, Titans are seen in the background, battling Atlans. Another is being harassed by a Sentinel Dragon.
- The Titans are possibly based on the giants depicted in Dante Alighieri's Divine Comedy. In the epic, the giants includes the Classical Greek Titans who fought to overthrow Zeus and the biblical giants such as Nimrod, who organized the construction of the Tower of Babel. They are imprisoned in between the Eighth and Ninth Circle of Hell.