Samur Maykr

The Seraphim is an entity mentioned in the lore of Doom (2016) and Doom Eternal about which little is currently known. One detail known for certain is that it was opposed to the forces of Hell: they are said to have gifted the Doom Slayer with super-human powers of speed and strength. In real-world mythology, seraphim are described as a high ranking and powerful caste of angels in the mythologies of, naturally opposing demons. Although the word is plural (the singular form is "seraph", in the context of Doom (2016) and Doom Eternal, the name applies to a single character.

Little information can be extracted from a few entries in the codex. Among these is a picture (an etching from the "Book of Daeva") that is speculated to contain an image of the Seraphim in the upper left corner. This mysterious figure appears again in the box art for Doom Eternal.

He has never been seen without his cloak. In Doom Eternal it is shown that he has typical Maykr Angel tentacles and hands, but he has no staff, Orator Ring or head crest that can be seen beneath his cloak.

Doom (2016)
The Seraphim does not directly appear, but is mentioned in the Codex to have granted the Doom Slayer his power. The Codex shows him watching over Doom Slayer battling demons.

Doom Eternal
In a flashback from the Doom Slayer's point of view that is corroborated by Codex entries, it is revealed that the Seraphim is the Maykr known as Samur Maykr, the former chancellor of the Khan Maykr who went rogue for unknown reasons; as no Maykr is thought to be able to disobey the Khan Maykr, his rebellion opens up the further question as to how he could do so. Having stolen the essence of the Father from Urdak in defiance of the Khan Maykr, Samur was impressed by the Doom Slayer and secretly gifted him superhuman strength, speed, and endurance using a Maykr device called the "Divinity Machine". He disappeared shortly afterwards, and was presumed exiled by the Argenta.

His ultimate fate is unknown, as are his motives for aiding the Slayer. Certain similarities between him and Samuel Hayden have prompted speculation the two characters might be somehow connected.

When the Doom Slayer enters the Urdak building where the Khan Maykr is attempting to revive the Icon of Sin, he is greeted by a voice telling him "Welcome home, Seraphim". Whether this message is simply an automated response without further meaning, the detection of the foreign bodies injected in the Slayer's bloodstream by the Divinity Machine, or detection of Samuel Hayden's presence through the connection between the Fortress of Doom and the Praetor suit, or something else is not made explicit.