Protagonist

The protagonist is the main character in a story. In a game, it is the player's character.

Doom

 * Doom's protagonist is left nameless in all installments of the core Doom franchise. In Doom 3, the main campaign, Resurrection of Evil, and The Lost Mission all feature separate protagonists; whereas it is implied the same marine went through Ultimate Doom, Doom II, and Final Doom.

Several mods give an identity to the player character. A few notable examples:
 * Icarus: Alien Vanguard and Daedalus: Alien Defense: Dave Razor, Space Marine, named by contest.
 * Mordeth: Norman Ash, who got trapped in Hell after severing the invasion portal from the wrong side.

Heretic

 * Corvus is the name of the player character given in Heretic II; who is said to be the vanquisher of D'Sparil.

Hexen

 * Baratus the fighter, Daedolon the mage, and Parias the cleric are the available characters.

Strife

 * Strifeguy is said to be a mercenary.

Other games

 * Chex Quest's protagonist is named Fred Chexter and often referred to as the Chex Warrior.
 * Hacx features Danny Evanger, a hacker and ex-convict.
 * Harmony is named after the player's character.