DOOM -- that is to say the video game from 2016 and not the one from nearly 25 years ago -- doesn't waste a lot of time with exposition. It's... Kind of the game's defining characteristic. Within the first five minutes of the game its protagonist literally punches plot and character development. Like, with their fist. It's great.
If you're not too overawed by the game's unmitigated demon murder, however, you'll notice a weirdly intricate plot that somehow manages to weave every DOOM game before the reboot into an ongoing timeline. Yes: Doom, Doom 2, Doom 3, and even Pinky-demon-loving Doom 64 could all theoretically fall into a shared universe.
This is in spite of the fact that most of the Doom games have no more story than what someone was able to fit onto a single page of a player manual. Nevertheless it all makes a weird sort of sense -- enough so that quite a lot has been written about this "unifying theory."
The skinny of it goes like this. The original Doom takes place on Mars. The Union Aerospace Corporation -- a running entity through most of the Doom games -- is screwing around with teleportation. Pretty soon they screw up said experiments by accidentally opening a portal to Hell. Which seems a bit like testing lipstick on chimps and accidentally causing the zombie outbreak from 28 Days Later but hey! These things happen (in Doom games, anyway).
The aptly named Doom 2: Hell on Earth brings the fight home after the lone marine that defeated the demons of the first game learns they made it to the human homeworld. He proceeds to kill them as well. Of course, he can't catch a breather because Doom 64 -- not just a port of the original game to Nintendo's console but an entirely new sequel -- sends the Marine back to Mars to mop up the remaining demons.
That game ends with the marine staying in Hell indefinitely to continue doing what he loves best: killing demons.
Meanwhile, Doom 3 picks up with a notably different tone and protagonist from those three games. In this installment, humanity picks up its old teleportation research, which it found in the ashes of the old Doom 2 world, and once again opens a portal to Hell. Apparently an apocalypse wiping out all of recorded history makes it really easy to repeat past mistakes.
Finally, when DOOM 2016 starts, Hell is a pretty well-understood entity. There are cults devoted to it. It's part of the corporate structure of the UAC. In fact, the company is mining the dimension for unlimited, clean energy. Which, if this unifying theory is to be believed, comes to a halt once they find a legendary warrior wrapped up in stone inside the underworld.
Who else could it be besides the one, the only, the Doom marine who stayed in Hell after Doom 64? In-game text and audio logs back this up pretty substantially, too. Meaning Doom of all series might just have one of the longest-running plotlines in all of video games...
If you're one of the dubiously lucky people that played Destiny when it launched in 2014, you know that the game originally had next to no story to speak of. If you're one of the inarguably unlucky people who searched for the game's missing plot in Grimoire Cards, you have our condolences.
Grimoire Cards, for those more fortunate souls out there, are how this bizarrely inexplicable first-person shooter dumps its lore. Lots of video games do something similar. They'll hide whatever exposition is deemed too minute for the main plot in optional text and audio logs. The difference is that most games also let you read or listen to that stuff in... The game. Destiny, for whatever reason, forces you to look them up in an app. These are the Grimoire Cards.
Most of these cards are smoke and mirrors -- half-sensical nonsense words written to sound like something that doesn't really mean anything. A few of them, however, are pretty damn interesting. Specifically the ones about Oryx, the Taken King -- final boss of Destiny's best expansion, the, uh... The Taken King.
By the time he shows up in Destiny Oryx is a pretty heavy hitter. He's got an army, a moon-sized battleship, and magic powers that let him "take," or basically mind control most of his foes. It didn't start out that way, however, as we learn from a series of Grimoire Cards that detail the monarch's rise to power -- as well as their fall from grace.
Oryx, you see, used to be Aurash. She was the princess of hard-living race of bug people with a lifespan of about 10 years. Her father became obsessed with an apocalyptic prophecy. So much so that one of his courtiers instigated a coup out of fear that he'd gone crazy. Aurash and her two sisters headed for the hills rather than get whatever the short-lived bug-person equivalent of a guillotine is and promised to regain their throne.
Well, they did, but only by making deals with undead worms that gave up their souls to the Darkness: Destiny's unseen ultimate villain. This encouraged Aurash to morph into Auryx. Auryx then became Oryx when he killed his parasitic worm, who had addicted him to "inquisitiveness," and The Taken King became a nihilistic space god. Unfortunately for the players of Destiny, Oryx's inquisitiveness usually manifested itself as a desire to learn how best to kill every living species in his way. It was a nasty turn of events for the once pretty noble creature, Aurash, but one helluva a backstory for a good villain.