Marauder

The Marauder is a new monster which occurs in Doom Eternal. It is a humanoid demon with a skull-like head bearing large, prominent horns. It has blueish-gray skin and wears green armor which closely resembles the Praetor suit. It keeps a garland of skulls around its left thigh, indicating that it may act as a headhunter. It wields a super shotgun and an Argent double-bladed battle axe.

Pre-release
Hugo Martin promised at the 2018 convention that there is a story reason behind the appearance of the Marauder and its resemblence to the Doom Slayer which will be revealed in the game.

E3 2019
The Marauder appears at the end of the story trailer of Doom Eternal, as the Doom Slayer pulls out a chainsaw in response while it is swinging its battle axe.

At E3 2019 the Marauder was revealed to be one of the five established playable demons in the new Doom Eternal multiplayer Battlemode.

2020 trailer
The Marauder appears in the second official trailer for Doom Eternal, walking out of a red portal facing the Doom Slayer. It is revealed that he can speak, and he refers to the Doom Slayer as an "usurper" and a "false idol," perhaps hinting at facets of the Slayer's history in Night Sentinel culture that have not yet been fully revealed.

Mechanics so far
The Marauder has been called by Hugo Martin as a “black belt” demon, saying that you can’t just run and gun it like you may with other demons. The Marauder has certain mechanics that need to be studied and dealt with carefully.

Super Shotgun: The Marauder uses its super shotgun whenever the player gets close to the Marauder, it uses it quite fast as well making it unlikely that the player will be able to dash out of the way.

Argent Axe: The Argent Axe is particularly interesting as it has two functionalities. It is used as a melee weapon from a medium distance, where the Marauder does a huge step in swing to hit the player. It also has a long range attack where the Marauder sends out a wave of argent energy to hit the player.

Argent Shield: The Marauder can shield himself from all incoming damage from the front by using his shield. The shield glows red-orange and displays the Doom Slayer’s logo. It acts similarly to the shield wielded by some Zombiemen, however it does not seem to be affected by Plasma and so cannot be blown up.

Dash: The Marauder has a dash ability much like the Doom Slayer does. The Marauder often uses this to flank behind the player, it is possible to see where the Marauder has gone due to a streak of argent energy left behind when the Marauder dashes.

Summons: The Marauder can summon a hellhound (possibly a wolf) of argent energy. It glows red-orange like the Marauder’s shield and will move across the arena. It frequently attacks the player and can be an annoying (and quite damaging) distraction when facing the Marauder. It should be dealt with as soon as possible.

Special: The Marauder is resistant (but not invulnerable) to the BFG, and will deploy his shield whenever he takes damage. In order to properly damage the Marauder you must wait for him to use his mid range melee attack with the Argent Axe. During his melee animation his eyes flash green which indicates your time to strike. Attack during this time successfully and the Marauder staggers slightly as well as taking all the damage you just dealt.