Ahzrak seeks the Heart of Argent to gain godlike power from the soul of the Wraith so he can rule over Hell as the head of the High Council of Hell. He is wary of the Slayer and often avoids confronting him, telling the Witch and his subordinates to focus on breaking the Argenta first, unleashing a horde on Hebeth after failing to find what he sought at Khalim. He leads an attack on the City of Aratum where the Heart of Argent is supposedly sealed and has a portion of the demon horde attack the Sentinel's barracks to divert the Slayer's attention. By the time the Marine arrives, the prince attempts to seize the artifact, only to be stopped by Novik who seizes it as Valen detonated the charges, distracting Ahzrak long enough to escape the collapsing city. He later lays siege on a Sentinel city, soon coming after Novik and beats him to seize the Heart of Argent, only to find out he only had the amulet but the second portion, the energy source, was lacking. When the Slayer pilots an Atlan that was damaged earlier during the battle after being thrown out of the balcony by the Witch, the demonic prince is then teleported to avoid getting obliterated by the robot's cannon. He later hijacks a Maykr drone and slaughters all other drones in his vicinity before coming in contact with the Kreed Maykr, who had just lost control over the Doom Slayer and was forced to stay near the front line lest he would be executed by the Khan Maykr. Upon establishing contact, Ahzrak offers to enlist him in his quest for the power source of the Heart of Argent. After the Doom Slayer is incapacitated by the Wraith power upon contact with Thira, he acquires the Wraith's power with the help of the Witch and has the Slayer imprisoned in the Cosmic Realm, knowing that killing him won't be a permanent solution. As he lays the final assault on the Sentinel Stronghold, he fights the Slayer and manages to seriously wound him both physically and emotionally, the physical part being by stabbing him in the abdomen and the emotional part by killing Serrat, the Slayer's loyal mount. After a lengthy battle, Ahzrak is defeated as the enraged Slayer rips out the heart of Argent from his body, rendering him back to his original form.

In command of the forces of Night Sentinels on air-combat, Thira receives her command and order through her father. She first encounter the Slayer when an invasion was launch on the base of the Sentinels, quickly begin to work with him in order to track down the forces of Ahzrak and stop him from destroying the people of the land. She was later granted power through the heart of Argent D'Nur, but was kidnapped shortly afterward by the prince of Hell Ahzrak. Doom Slayer managed to break through their forces in hopes of rescuing Thira, but the spirit of the ancient sentinel God destabilize him due to mis-interepting that he is doing harm to her. Thira is later released from her imprisonment as the Doom Slayer kills the prince. She join forces with the rest of the army in the battle against hell. In the end, Thira developed a sense of honor to the Slayer, as she vow to lead her people to the right ideals in honor of the legacy the Slayer has left for them.

Valen was one of the Night Sentinels commanders who led countless battles against the forces of Hell. However, after his son perished in battle, he was driven mad and relentlessly haunted by demonic visions of his son living in a tortured existence. Valen soon fell into desperation to bring his son back to life at the cost of betraying his kin.[1]

Novik used to be a boastful and arrogant warrior during his youth but becoming tempered as he becomes older and wiser. He is the longest monarch of Argent D'Nur who rules the realm for four decades. He fathered one daughter, princess Thira with his late wife.

The Witch is the secondary antagonist of Doom: The Dark Ages. Born from the congealed madness of the Cosmic Realm, Ulsamir is a living conduit for the dark magic coursing through her alien dimension. Her current body is but a temporary vessel, fragile and fleeting, used to manifest her malicious spirit in the physical world. Though she and her cult of chaos worshippers have allied with Prince Ahzrak, Ulsamir's allegiance is tenuous.