The character is introduced in the first film, Underworld, as an elite vampire assassin known as a "Death Dealer" who hunts down the Lycans for allegedly murdering her family.

She becomes attracted to a human named Michael Corvin, and upon discovering that her sire and adoptive father Viktor was actually responsible for the death of her family, defects from the vampire clan.

This can continue even to the point of endangering herself, such as when she passed out from blood loss at the wheel of her car after Michael warned her against driving in her condition.

In her Underworld official bio, it is stated that she "trusts almost no-one", and that she has a "passion for truth, albeit laced with vengeance", which "traps her in a reluctantly violent and tragic purpose".

[3] After centuries of militaristic discipline, having served as a Death Dealer of the vampire clan, Selene had long since developed a near-impervious, stoic external demeanor.

In the first installment, Kraven, who fancies himself as her suitor, complains that she pays far too much attention to hunting and killing Lycans, and that she takes "this warrior business far too seriously".

She dodges his social gatherings, she outright rejects his romantic advances at every turn, in public and in private and she prefers to dedicate her every waking hour into her calling as a Death Dealer.

In Underworld: Awakening, her own daughter easily misinterprets her behaviour for being "as cold as one already dead", before Selene explains that her heart isn't cold, but it is broken (as Michael is missing at the time) Selene is also in the habit of downplaying any pain or wounds she has received - a habit of hers that Michael has since become familiar with.

Cracks in Selene's emotional armour start to show themselves when she and then-human Michael Corvin meet for the first time at a subway, moments before a shootout, at the beginning of the first film.

The two experience a mutual "dynamic attraction" at first sight and things start to escalate between the two of them, even after she learns that Michael has been bitten by a lycan while she was trying to protect him from them.

When her family was murdered, she went on a revenge spree against the Lycans (whom she had been led to believe were responsible by Viktor) that lasted over six centuries, until the truth was revealed to her.

When she learns of Viktor's hand in her family's murder and sees him about to kill Michael, she slices through his head with his own sword the first shot she gets, without hesitation.

He should have killed you with the rest of your family" (in the novelisation, Markus also calls them "insignificant"); in a fit of rage, Selene snaps the wing talon off at a joint, using it to stab him through the head before pushing him into the spinning rotors of a helicopter.

As revealed in the first & second films, Selene is born to a Hungarian family; her father, mother, her older sister Cecilia, and her baby twin nieces.

At some point, Selene's father is approached by a powerful warlord named Viktor with a commission to design and build a prison.

According to the novelisations, Selene's father is well known as both a stone mason and blacksmith; and the commission involves the excavation of a new dungeon and prison under a fortress of Viktor's, as well as striking two unique keys for one cell in particular.

She also learns the truth about the identity of her family's killer from Kraven; she strikes Viktor down while the Elder is preoccupied fighting Michael.

After narrowly escaping Markus and the sunlight, Selene and Michael take refuge in a warehouse and begin a sexual relationship.

Tanis tells her the truth about her family's slaughter, (they were killed after Lucian began his revolution to keep William from being freed,) and reveals to her that, contrary to popular belief, Markus, not Viktor, is the original vampire.

Alexander, dying from his son's attack, tells Selene that the only way to defeat Markus and William is to drink his legendary immortal blood, adding that she will become "The Future".

Selene, empowered by Alexander's ancient and pure blood, tears away the talon and drives it upwards through Markus's skull before throwing him into the moving rotor blades and killing him.

The opening scene of the first Underworld film is then shown with the voice of vampire Kraven revealing to Selene that it was Viktor who killed her family, not the Lycans.

In Underworld: Awakening, Selene escapes imprisonment to find herself in a world where humans have discovered the existence of both Vampire and Lycan clans, and are conducting an all-out war to eradicate both immortal species.

[4] However, Selene and her two new allies; David (a young vampire) and Detective Sebastian (who lost his wife after being discovered as a vampire), discover a hidden conspiracy from rogue members of the Lycan clan within the humans' war against both species, and also finds that she has mothered a child with Michael, Eve, who was born during Selene's suspended animation.

Selene battles to rescue Eve and Michael, facing a 'Super Lycan', with abilities similar to her own including incredible healing rate and an immunity to silver.

Earlier in the film David offers her the opportunity to return to the vampire coven, in hopes she will consent to train a new generation of Death Dealers in response to both the human and Lycan threats, as many of their numbers are either in hiding from their enemies or dead.

"[5] "It was quite a challenge for me to play an action heroine and pull off all that training when [in real life] I can't catch a ball if it's coming my way.

Kate Beckinsale, who portrayed Selene in Underworld, expressed interest in reprising her role for the sequel and the prequel.

The previewing was well-received as hundreds of fans waited hours to see a clip of the film as well as Kate Beckinsale and the other stars of the movie.

[16] In a review for Underworld: Awakening, a top critic from Variety said "Once again, Beckinsale brings an impressive physicality and subzero cool to her portrayal of Selene".