Overlord (series)/WMG

Overlord is a sequel to the Dungeon Keeper series
Something the creators probably couldn't have driven home harder if they'd tried. The games have very similar themes (albeit different genres) and even many of the surface elements are similar, such as the tower heart and the visuals of the health meters. Obviously, then, it makes sense to connect the stories. Conveniently, the long-since-vanished Dungeon Keeper III was set to see the eponymous Keeper emerge into the overworld. Apparently the Keeper succeeded, becoming an Overlord into the bargain, with a tower instead of a dungeon for a home. Such a pity he would be destroyed by those ever-invading heroes, but hey, it gave Overlord a functional Backstory.
 * ...you know, that makes perfect sense. At the very least, I'd be surprised if none of the development team had ever played DK. Heck, your first quest is to find the Tower Heart.
 * Rhianna Pratchett who is responsible for it's story was a writer for the gaming magazine PC Zone UK for a fairly long period of time so it's pretty much a dead cert' that there's at least a small amount of creative inspiration from Dungeon Keeper.
 * Weren't the titular Dungeon Keeper extraplanar beings? Also, they were kinda incorporeal (requiring the dungeon heart to manifest any power). One would wonder how the transition from underground spirit to above ground tower dwelling armored figure took place. Then again, the original overlord DID survive the destruction of his body and manage to possess the wizard, then the jester. Perhaps there is truth to this WMG.
 * You were an incorporeal creature, but you worked for Horny, who was not.
 * DK is never entirely clear on whether the Keeper has a true physical presence (the Mentor joked back and forth on the subject, as far as I recall) but he could at the very least possess creatures, so he may have simply been possessing one in the fight. Or perhaps having a physical form was necessary in his escape from the underworld. In fact, given the nature of the Keeper as established in DK, I suppose the ruination of the tower would have been the thing that shattered his power. Presumably he was only able to survive to possess the Wizard thanks to the tower heart remaining intact, albeit removed from its socket.

Overlord is a prequel to the Dungeon Keeper series
In Overlord: Raising Hell,. Over time, he becomes less of a Guy In Armored Suit (which isn't practical for The Abyss) and more of an Eldritch Abomination, a form that simply works better. Unable to return to the Real World in any practical matter, the Overlord settles for an intermediary: the underground dungeons of Dungeon Keeper. He becomes the Dungeon Keeper, and the Dungeon Heart is what the Overlord magically-evolved into. It makes perfect sense within the mechanics of Dungeon Keeper: Where do all your minions in Dungeon Keeper come from? Portals, Bottomless Pits that actually have a bottom, and that bottom is the Overlordian Abyss. Other Keepers? Bad Guys (and former Overlords) who have done the same thing you have. Horned Demons in DK 1 being unruly and difficult? The Overlord-Turned-Dungeon-keeper killed all but one, and brainwashed it into believing it was the Big Bad instead of The Dragon it really was. Where did the O-T-D-K get that idea from? Gnarl.

The Explosion of the Tower Heart caused Warhammer40k Warp to seep into the world and infect it
We have a human Empire led by a Golden Emperor that's dedicated to the eradication of all other creatures because they're 'tainted' with magic: The Imperium. We have a race of decadent/ineffectual scimitar swinging elves who are a dying breed and can be corrupted into sin and darkness: Eldar. The area around the first Dark Tower is saturated by a magical residue that corrupts and warps anyone who touches it into mindless savage mutated beasts: The Warp. Giant spiders/salamanders monsters that only want to devour until their hive queen/king is dead: Tyranids. And all of this is opposed by a force of pure evil that either kills and slaughters everything and everyone in its path (Khorne) or a schemer and plotter who enslaves people so that they may work towards his dark goals (Tzeentch). And of course, you have the minions. Scaly, toothy, scabby, bad manners and always ALWAYS ready to start a WAAAAGH!! What more proof do you need?!
 * Also the fact that the Cataclysm was caused by gives similarities to the  story.

In a DLC/Expansion Pack for Overlord II, the Overlord from the original game (the one you play as, not the Wizard) will come back. With a vengeance.
Most evidence suggests that the canon ending for the first game was the 0% corruption one, or at least a low corruption one, making the old Overlord significantly less evil than his descendant, even if you go the Domination route all the way. So when he gets out of the Abyss with his armies, it'll be as a Noble Demon and/or Dark Messiah opposing your reign, leaving you to face him, with the combined power of the Abyss and the remnants of the forces of Light (since the elves owe him for, y'know, preventing their genocide) at his disposal. Luke I Am Your Father moment/parody optional. "(Both overlord just stare at each other.) Gnarl: Family meetings are always akward"
 * Considering both are Villainous Mimes, I can already see situation:

Gnarl is the real ruler of the Overlord's domain
Every time the Overlord dies or is otherwise indisposed, Gnarl leads the Minions, but because the Tower Objects won't respond to him, he can't fill the power vacuum and rule the Dark Tower. For that reason he's forced to keep recruiting new Overlords, but uses each one as his pawn. Isn't it strange that Gnarl spends all his time comfortable in the Tower, while the Overlord is the one putting his life on the line and doing all the grunt work. Gnarl merely maintains an illusion of subservience while he rules behind the Overlord's back.
 * You spend the entirety of both games doing whatever Gnarl says. At the end of the first he says he'd be "glad to have you back - I mean, serve you again". He pretty clearly sees himself as (and probably is) the real power behind the throne.
 * Don't forget that in both game he fairly early on gets you to get a mistress to help keep you pleasantly distracted.
 * That or he's trying to start a continuous lineage so he doesn't have to bust his ass into finding an Overlord every time one dies.
 * Makes sense. So far we have seen that all Overlords prior 4th have more or less "accidentally" become Overlord. 3th was resurrected. After he was lost, Gnarl would have easily get new Overlord by raising Overlad, if not for the Rose to run off. Having secured legacy makes it more easy to get new Overlord to work with him, since "he has always been there".
 * Notice how you can target anyone in the castle for abuse, even your own mistresses, except Gnarl? His illusion of subservience is thin at best; he uses the imperative freely enough to earn a stomped throat from a real tyrant, yet you can't do anything to remind him of his place.

Lord Gromgard is the Old Overlord
Starting a genocidal war between the elves and dwarves that would culminate with the near-extinction of one side is quite the Moral Event Horizon, even if it was Gnarl's idea. What if Lord Gromgard liked the notion of playing his enemies against each other, and grew to embrace it as an older, mightier Overlord. Manipulating his enemies to kill each other for him is certainly the Modus Operandi of the Old Overlord (Wizard) of the first game. Nevermind that the prequel is supposed to take place centuries before the first game - with his skill at Grand Theft Me, Gromgard could easily have possessed a whole string of Overlords leading all the way to the present.

The hero who would become the new Overlord in the original game was a bard.
The heroes who survived the battle and became corrupted had to number seven for the deadly sins theme,but this also gave us a quite large and well balanced party with all the roles filled, assuming the paladin could provide the necessary amount of healing, but there's always room for the traditional bard. Sure the nameless former hero could have had the same class as one of his mates, but I just find it funny that, in the words of another bard, "the guy who goes into a dungeon and sings" ends up ruler of all the land. And if you don't fancy bards, introduce another obscure,"should be big time in my opinion" class in its place like a warlock or factotum. "Elan: Crush, crush, crush the rebelling peasants."
 * It would explain why he wasn't affected by the musician at the halfling party who forces the minions to dance. In his previous life, he was used to playing the same songs himself.
 * And now I can't help but imagine Elan from Order of the Stick becoming the next Big Bad after they take down Xykon. And it would be hilarious.
 * Well, given the true identity of his father he'd definitely be continuing the family tradition if he did.


 * It would also explain why he is a Magic Knight and can cast spells in armor (yes, I know technically D&D Bards can only cast spells in light armor but it's close enough).

Overlords serve as a "queen" to minions.
They can't process life force naturally, due to their domain in the Netherworld. They need to run it through Overlord first. In exchange for the Overlord providing this processing effect, minions offer unconditional loyalty. Think bees with a more hardcore queen. The Overlord "spawns" new minions by converting standard life force into minion life force. Thus, the reason why minions seek new Overlords and guide them to the "evil" path is that they need new "Queen/King" to collect this life force to spawn new minions. Gnarl only serves as temporal "hive mind", since he can think, but can't process life force. Alternatively, Gnarl is some former Overlord who eventually turned into minion himself after years of collecting and processing life force. Also, now you think of Overlord and Overlad as crossdressers.

Summoner wraiths in raising hell were old overlords.

 * The forgotten god seemed much more interested in punishing fallen heroes than out and out evil people, it seems likely that the robed wraits (reapers?) were old overlords. Point 1.) They have the appearance of minions, this may seem a bit odd, but it's also a tad ironic, since wraiths serve the fallen god, it would be fitting for them to be turned into minions, the master becoming the servant. Point 2.) They have the ability to summon more wraith thralls on command, though their control is lacking, they're basically generals calling on an infinite supply to serve them, much like yourself. Point 3.) Kill one and watch how they die, this is the strongest thing that points to them being old overlords, they die exactly how all three playable overlords die in the series (A yellow light opens beneath them and drag them in).

The classes for the eight heroes are:
Kahn was the warrior, Jewel was the thief, Sir William was the pally, Goldo was the ranger, Oberon was the priest, the Wizard was the sorcerer, Melvin was the bard, and  was the wizard's apprentice.
 * Or a henchman.
 * Alternatively, Khan was the barbarian/berserker, the Overlord was the fighter.