One of the first details revealed about DOOM 4 was that it would feature a resistance group made up of civilians who had taken up arms against the military. In addition to the player, the resistance group had a few defined characters as well. Bradley, an old veteran with an eyepatch. Augustus, a man who we don’t know much about but was featured in several animation tests. Stove, a large buff man. Ancira, a doomsday prophet. There’s also an unnamed woman seen in the Blur Studio footage who seems to be a leader figure in the group. The actor Danny Trejo’s likeness was also used for a character.
Very little is known about the military characters in DOOM 4. The late actor Gene Hackman’s likeness was used for a character that might have been some kind of UAC executive, and there’s an unnamed woman with a purple outfit who could also be related to the UAC. But this is speculation.
Several returning demons were used as enemies in DOOM 4, albeit with some very different designs in some cases. The returning demons known to date were Former/Possessed Humans, two versions of the Imp, Lost Souls, Cacodemons, Archviles and the Spider Mastermind. Several unnamed demons also appeared in footage of the game, such as a snake-like demon with a humanoid woman as its shell which split open to reveal its true self, conjoined demons, and a large demon attached to a wall. In addition to these demons several other ones have been seen in storyboards and concept art, including two designs of a Pinkie (seemingly not spelled Pinky).