Doom Slayer

Doom Slayer is the protagonist and playable character in Doom (2016), Quake Champions, and in the upcoming Doom Eternal games.

He is intended to be the latest iteration and continuation of the classic Doom Marine (B.J. Blazkowicz III) who has been the main protagonist for most the series, and who, according to Tom Hall (who worked on the original Doom), is the son or grandson of Commander Keen.

Personality
Unlike some of his earlier appearances in the series, he shows a little more emotion, evident when he angrily destroys the communication panels that Samuel Hayden tries to use and ask for assistance from the marine after the explanation of necessary measures and sacrifices being taken (shortly before the Doom Marine sweeps his vision across several human corpses in the room). He also demonstrates this during the penultimate mission, when he decides to take a back-up of VEGA's code before destroying it, despite not being asked to do it.

Abilities

 * Badass Incarnate: Having become an icon in gaming, and battling the forces of Hell for decades, has earned the Doom Marine the status of being an absolute badass. This makes him an invincible and unstoppable force to be reckoned with (though it depends on the player's actions).
 * Superhuman Abilities: The Doom Marine has shown to possess immense physical Strength, Endurance and Durability, and superior Speed and Stamina. He outmaneuvers his opponents with great speed, avoiding their attacks, and yet is capable of enduring the hits that the Demons are able to land. His strength is sufficient to grapple and overpower superhumanly strong demons in hand-to-hand combat, and perform gory "Glory Kills" to ensure their complete destruction. These abilities are all augmented by the Doom Marines Praetor Suit and are used when fighting against the Demons of Hell.
 * Destruction Empowerment: The most unique thing about the Doom Marine is his ability to grow stronger and become even more tenacious with every demon he kills. According to the game's lore, this is the result of the Seraphim giving the Doom Marine the ability to absorb the souls of those he killed.
 * Argent Energy Absorption: The Doom Marine can absorb Argent Energy via his Praetor Suit, which reroutes it throughout the suits subsystems and into his body. This allows him to increase either his Health, Armour or Ammo to maximum levels.
 * Rune Absorption and Usage: Through some unknown means, the Doom Marine is able to use mystic runes that he gains upon completing trials. Once a trial is complete, the Marine can then use a rune to gain new abilities.
 * Powerup Usage: Whereas powerups (such as Berserk and Haste) in the game are described as killing or driving human users mad, the Doom Marine can use these without any trouble, sustaining full control and not taking any damage to either his body or mind from using such artifacts multiple times.
 * Expert Combatant: The Doom marine is a highly trained and experienced combatant, even when lacking of ammo and weapons, he can slay demons just with his bare-hands alone, without the need of any melee weapon, he can defeat and tear apart demons far bigger and stronger than him just with his own skills in hand-to-hand combat. With the Praetor suit, this skills are far increased, making him a monster in both armed and unarmed combat.
 * Weapon Mastery: The Doom Marine is capable of using any weapon or firearm in his possession with master proficiency. He can use all firearms he comes across with great effect, while also upgrading and modifying his arsenal. He is also capable of carrying a vast amount of weapons, carrying up to 12 weapons including special weapons (Chainsaw and BFG) and grenades.
 * Advanced Intellect: The Doom Marine has shown to possess a high level of intelligence as he is able to use technology from other worlds with no signs of unfamiliarity, despite resorting to violence.

Trivia

 * The game attempts to leave the DOOM Marine as mysterious as possible and points out that no one knows if he is human, god or some kind of demon. This is never cleared up, but there are many hints to him probably having some more terrestrial origin (and that time travel was involved), but it is never confirmed.
 * Doom Slayer is the main official title for this character in both Doom (2016) and Quake Champions and is the title used for the Slayer's Testaments.
 * The title "Doom Marine" or "DOOM Marine" first appears as a title for the main player character appears in earlier material including the Doom RPG website, and the introduction in the Doom 3: BFG Edition manual.