Think the Underworld series is just bloody vampire-versus-werewolf action, a never-ending

hail of ultraviolet bullets, and pretty people in tight leather? Think again. Look a little

deeper and you'll find a complex mythology that'll give even the densest fantasy novel

a run for its money.

If you need some help figuring out exactly what's going on in all of the Underworld films

and you don't mind spoiling some of the franchise's big reveals, here's everything you need to

know about Underworld's monstrous mythology.

Back in the early fifth century, Alexander Corvinus was just your regular, run-of-the-mill

Hungarian warlord...until he returned from a campaign to find that his entire village

had succumbed to a rare plague.

Alexander contracted the disease, too, but thanks to a bizarre genetic mutation, he didn't

just survive the disease it actually made him immortal. Alexander passed his immortality

on to his sons, the twin brothers William and Marcus, and an unnamed third child.

But the Corvinus clan had worse times ahead. William was bitten by a wolf and the bite

interacted with the virus in his bloodstream to give him special powers, essentially transforming

him into the first werewolf. Shortly afterwards, Marcus was bitten by a bat, making him the

first vampire. Meanwhile, Alexander's third son, whose immortality lay dormant, passed

his latent powers on to his offspring as a recessive trait, creating entire generations

of would-be immortals.

Now, it's worth noting that the newly transformed William wasn't the type of creature that we'd

typically call a werewolf at least not in the way we traditionally know them. Yes, he

took the form of a bloodthirsty beast who could rip regular human beings apart with

ease. Yes, his bites were infectious, and turned his victims if they lived into werewolves

themselves. However, as a result of their infections, none of these early werewolves

could ever turn back into human beings. For William and his descendants, it was all-wolf,

all the time.

This presented a problem for Marcus. Mentally, the werewolves were more beasts than men,

and it wasn't long before they were chomping on peasants and nobles alike as they cut a

bloody swath across Europe. Despite Marcus' best efforts, William couldn't be controlled.

Something had to be done.

Marcus decided to raise an army and take the fight to William himself, beginning the vampire

versus werewolf war. However, the twins' father, Alexander, decided on a different approach.

Instead of fighting against his son, Alexander marshaled his own forces and dedicated his

ever-lasting life to keeping the Immortals' existence secret.

"The innocents who witnessed, they've been silenced?"

"But otherwise unharmed, as ordered."

Before we get too far, it's worth noting that Underworld's versions of vampires like its

werewolves aren't exactly like the ones you normally find in books, movies, and TV shows.

The basics are the same: these are still immortal beings who feed on blood. But Underworld's

vamps have a variety of powers and abilities that you won't find anywhere else.

For one, the Underworld vampires can't change into bats or other animals, although ultra-powerful

ones like Marcus can assume a monstrous, winged form. Instead, Underworld's undead have super-strength,

heightened reflexes, and an accelerated healing factor. You also can't be a vampire and a

werewolf at the same time. With a couple of rare exceptions, werewolf bites are fatal

to vampires, and vice versa.

More importantly, for these vampires, drinking someone else's blood isn't just a form of

nourishment. It also lets them relive the victim's memories, a skill that's often used

to tell whether or not the target is telling the truth. If a vampire has special powers

like, say, immunity to sunlight sharing their blood will pass those abilities on to others.

Finally, even though they're technically dead, Underworld's vampires can still mate and have

children, who also end up as vampires, naturally. Given Underworld's focus on legacy and bloodlines,

that last point is very, very important.

If you're going to fight a war, you need an army, and as the vampire-werewolf conflict

began to heat up, Marcus knew exactly where to find one. Viktor, a ruthless warlord known

for his cruel and overbearing demeanor, was nearing the end of his life when Marcus approached

him with an offer he couldn't refuse. Marcus wanted Viktor's military expertise and his

expansive army. Viktor didn't want to die. So, they made a deal: Marcus turned Viktor

and his followers into vampires, making them immortal. In return, Viktor devoted his army

to Marcus' cause.

The Vampire-Werewolf war lasted for centuries. The werewolf hordes began to grow, while Viktor's

soldiers, now known as Death Dealers, grew increasingly skilled at putting the beasts

out of their misery. Finally, the conflict came to a head in 1202 A.D when Marcus, Viktor,

and a third elder vampire named Amelia tracked William to a remote village. After launching

a swift and brutal attack, the vampires took William hostage, although not without suffering

a number of casualties.

"Locked him away, Viktor's prisoner for all time."

However, Viktor wounded William in the attack, enraging Marcus. Now, Marcus couldn't challenge

Viktor directly even after all of those years, the Death Dealers remained loyal to their

first master but that didn't mean that he couldn't hold a grudge.

At some point in the intervening years, Viktor, Amelia, and Marcus together known as the three

Vampire Elders established the Chain, a system that splits power equally between the trio.

Under this structure, only one Elder remains active at a time, overseeing the world's various

vampire covens. The other two "sleep" in their coffins until it's their turn to rule. Every

hundred years or so, the Elders switch places. The current ruling Elder goes to sleep, while

the next in line takes their place.

Of course, while Marcus and Amelia were asleep, Viktor found that the Chain had other benefits,

too: mainly, that without the other Elders around to interfere, Viktor could solidify

his power. With the help of the vampire historian Andreas Tanis, Viktor convinced the Coven

that he, not Marcus, was the original vampire. He domesticated captive werewolves and used

them as slaves, and ensured that the Death Dealers remained loyal to him and only him.

In fact, Viktor would've killed Marcus as he slept and taken power outright if Marcus

hadn't taken one extremely important precaution. Before he went to sleep, Marcus told Viktor

that killing one of the original immortals would rob all their descendants of their powers.

If Marcus died, there would be no more vampires. And if William perished, the werewolves would

be finished, too.

Of course, none of that was true Marcus was simply trying to keep Viktor at bay. But the

lie worked. Viktor was unwilling to lose either his immortality or his werewolf slaves, and

decided to let William and Marcus live, content to plot from the shadows instead.

In the early 13th century, things were going pretty well for Viktor. He was, for all intents

and purposes, the most revered of all of the vampires. His daughter, Sonja, was a fierce

Death Dealer and was on the path to becoming the fourth vampire Elder. While William's

defeat didn't end the werewolf threat, Viktor's rivals had been dealt a significant blow by

his capture. Besides, there was no way William was getting free. Viktor gave one key to William's

cell to Sonja for safekeeping, and had the other key grafted onto his ribcage, where

Marcus couldn't find it. Talk about a good hiding spot!

Everything changed when one of Viktor's slaves gave birth to Lucian, the first member of

a new species of werewolf. Known as Lycans, this new breed appeared human until the moon

turned full, at which point they turned into monstrous beasts. As a result, they were smarter

and also easier to control than regular werewolves. Viktor immediately saw an opportunity.

"What do you think, Sonja, shall we make more?"

"Of him?"

"Like him."

Using Lucian's blood, Viktor created an entire army of Lycan slaves to guard the vampires'

stronghold from werewolf attacks during the day. A 200-year peace followed. And yet, even

Viktor couldn't plan for what happened next: Lucian and Sonja fell in love.

Naturally, Viktor wasn't a fan of vampire and Lycan romances, and Lucian and Sonja worked

hard to keep their love affair a secret. Unfortunately, they couldn't keep Viktor in the dark forever.

As Viktor became increasingly abusive towards Lucian, the disillusioned Lycan began discussing

rebellion with his fellow slaves. Meanwhile, Sonja became pregnant with Lucian's baby,

and the pair made plans to escape together.

Viktor caught on just in time. By drinking Sonja's blood, Viktor discovered the truth

about his daughter's deception. Quickly, everything fell apart. Viktor tied his daughter to a

stake and flooded the room with sunlight, forcing Lucian to watch as Sonja and their

unborn child were burned alive.

After the murder, Viktor left Lucian to wallow in his misery. But that was his biggest mistake:

It turns out that the moon that night was full, giving Lucian the strength he needed

to burst out of his chains. Lucian stole Sonja's pendant - which was actually one of the two

keys to William's prison - and rallied his forces. With the Lycans at his back, Lucian

decimated the vampiric forces and took their castle for his own. And so, the Vampire-Lycan

war began.

As the war raged on, Viktor made moves to consolidate his power. With the help of Andreas

Tanis, the vampire historian, Viktor framed Lucian for starting the war, making him the

vampires' sworn enemy. He also enlisted the help of a human architect to build a new prison

for William and then killed the architect's entire family when the building was complete

in order to preserve its secrets.

Well, almost his entire family. The architect had a daughter, named Selene, who reminded

Viktor so much of Sonja that the vampire couldn't bring himself to murder her. Instead, he transformed

Selene into a vampire, then lied to her, telling her that Lycans had killed her family. Selene

vowed to get revenge.

As Viktor's lies began to stack up, Tanis started to have a change of heart and began

revealing the truth. In response, Viktor accused Tanis of spreading "malicious lies" and, with

Selene's help, exiled him to a remote monastery. Meanwhile, Selene quickly became Viktor's

most talented and prolific Death Dealer, dispatching hundreds of Lycans over the next 600 years.

However, Selene wasn't the only Death Dealer with a knack for killing Lycans. One of Viktor's

original lieutenants, a vampire named Kraven, was almost as good. In fact, it was Kraven,

not Selene, who officially ended the Vampire-Lycan War, although his victory wasn't quite what

it seemed.

Sometime between Lucian's rebellion and the beginning of the first Underworld movie, Kraven

and a group of Death Dealers invaded Lucian's castle, hoping to bring the centuries-long

war to a close. It didn't go well for the vampires, who, except for Kraven, all died

in the attack. However, from all appearances, it went even worse for the Lycans. In the

aftermath, Lucian's castle burned, while Kraven emerged from the skirmish holding a piece

of Lucian's branded skin, using it as proof of the Lycan's death.

It was a ruse. Secretly, Kraven and Lucian were working together. Kraven received all

of the credit for ending the war, while Lucian and many of his fellow Lycans went into hiding,

waiting for the perfect time to strike - and it worked. When it was Amelia's turn to take

over as part of the Chain, Viktor appointed Kraven regent of the Old World Coven, the

oldest and most powerful group of vampires on the planet. As Viktor slept, Kraven made

plans to take over the coven permanently.

Lucian didn't waste his time in hiding. For one thing, he teamed up with the now-exiled

Andreas Tanis to develop deadly "ultraviolet bullets" that could drop vampires with a single

shot. Not only that, but in his quest to topple the vampiric regime, Lucian began researching

the mythical "hybrids," which combined the powers of Immortals, vampires, and werewolves

into one.

Only direct members of Alexander Corvinus' genetic bloodline could become hybrids. That

made William, Marcus, and Alexander himself candidates, but also meant that any ancestors

of Alexander's third son, who was mortal but carried the Immortality virus in his blood

as a recessive trait, were also possible hybrids. At the beginning of Underworld, Lucian is

secretly hunting for the unnamed son's descendants, hoping to infuse them with both Lycan and

vampire blood in order to create a new, all-powerful creature.

He's not doing this out of charity. Drinking a hybrid's blood magnifies a werewolf or a

vampires' existing powers while removing their weaknesses. Other effects are unknown. After

all, when Underworld begins, the only known hybrid - Lucian and Sonja's daughter - had

been killed in the womb.