Aside from being a sort of noir action film series, the Underworld film series interestingly parallels racial attitudes in society. Basically, how attitudes have done a 180 in Western society about race. How does it relate to race? The series is about vampires and werewolves, and the idea of interbreeding, or having "hybrid" offspring is a main plot point in the series, with some characters promoting it, and some decrying a hybrid would be "an abomination." Oh, this is one of those things that doesn't get interesting until the end, really.
Spoiler alert if you haven't seen it.
1. Underworld (2003)
In this original one, a female vampire falls in love with a man who is bitten and turned into a werewolf. Selene, the vampire, knows it is forbidden, but aids the newly turned werewolf anyway. Her vampire "father" (who turned her into a vampire centuries earlier) at first is shown to be a protector, but is later revealed to have executed his own vampire daughter after she fell in love with a werewolf and became pregnant. He protests "I did what was necessary to protect the species! The abomination growing in her womb was a betrayal of me, and of the coven!"
Confirming the metaphor for race, the leader of the lycans, who was the lover of the executed daughter, laments "We were slaves once. Yet I bore them no ill will." He desires to bring about a hybrid race, to end the blood conflict. Not unlike how a quick google search will reveal more than a few arabs or Africans saying how intermarriage between races would end problems, as one race would be absorbed into another. The interracial couple prevails and escapes.
2. UnderWorld Evolution (2006)
This shifts a little. In this, a "hybrid" wishes to unleash a race of hybrids upon the world. So, a slight shift? In even invokes a "God" figure who is the father of both races, and won't kill either of his sons.
3. Underworld: Rise of the Lycans (2009)
This movie fully promotes the werewolf from movie 1 (who wanted to create a hybrid race) as a hero, a veritable moses, who even does the Jesus pose while having sex with his vampire lover. (weird, I know.) He leads an uprising against slavemasters and takes over a castle. Heavy themes on races and bloodlines and arrogance of bigots. Remember, this movie was released on the tail end of the George W Bush years, as compassionate conservatism had it's grand finale.
4. Underworld Awakening (2012)
Now we jump forward several years into the Obama administration in the USA. (Things are still calm in Europe, mostly.) The interracial lover Selene wakes from a 10 year cryo sleep to find humans are exterminating vampires and werewolves, and werewolves want to use her hybrid child's dna to make themselves immune to silver. No werewolf hero, just "they are the enemy, kill them." Instead of a plot interested in ending that war, it's just war.
5. Underworld: Blood Wars (2016)
Released the same year Brexit happened, Trump happened, on the tail end of black groups burning various American cities and rioting. Instead of the earlier movies, the heroes talk of "the purest of us all" and "protecting the bloodline." The heroes are forced to flee from corrupt leaders and take refuge in a Nordic coven full of blond blue eyed vampires. Most telling, there is a mirror image of the first movie--a woman vampire who falls in love with a male werewolf. Instead of being heroes, they are the villains, and the movie celebrates when the female vampire is killed.
In short, this is a movie series that started out with the villains seeking to "protect the species" and the heroes dated inter racially/interspecies. And as cities burned in the USA and terror attacks shed blood in Europe, quickly shifted to full on "Protect the Bloodline." An interesting display of media following social attitudes.