Today is the 26th Anniversary of the launch of Doom 2, so John Romero was doing some trivia on Twitter and answered a burning question that lots of people wanted to know the answer to. I wasn't one of them and actually I can't guarantee that lots of people wanted to know the answer but I guess at least one person did. They saw their shot and they took it.
Now we know: "Doom Guy's name is Doom Guy." That's canon now because John Romero made Doom, so unless the other John wants to weigh in he's right.
Doom Guy's name is Doom Guy. https://t.co/jy9vBVKzPROctober 9, 2020
Finally, we know that his name is not Doomguy, but rather Doom Guy. Actually now that I think about it this is still more complicated. Guy is a surname of germanic origin common in France and England after the Norman conquests. So maybe Doom is a first name? Maybe it's short for something, like Adoom or Doominick? Does that mean we can't definitively use male pronouns for Doom Guy because Doom Guy might not be a Guy but might instead have the last name Guy? The plot thickens.
Doom Guy has had a lot of secondary names. There were Doom novels in the 90s, and Doom Guy had the name Flynn Taggart, but there were also Doom 3 novels and Doom Guy was named John Kane. The Doom 2016 and Doom Eternal games just call Doom Guy "The Doom Slayer," which is more of a title than a name and is therefore fine to call Doom Guy.
Anyways, the first DLC for Doom Eternal is called The Ancient Gods, Part One and is a standalone expansion out October 20th.