The story of a man and a monster
Even Castlevania's most diehard fans will admit that its labyrinth of a plotline is the narrative equivalent of a Rube Goldberg device. An ultimate evil here, a Belmont there, and suddenly we're ten-thousand years into the future with something called The Time Reaper. I know that after twenty or so games it's tough to keep the whole vampire thing fresh, but somewhere along the way you need to know when to rein it in.
The Brotherhood of Light done goofed and unleashed the Lords of Shadow
Gabriel Belmont's quest doesn't begin until the 11th century--the real story picks up a few centuries beforehand with the Brotherhood of Light. Founded by three of God's holiest champions, the order was created to battle the forces of darkness and maintain the balance between good and evil. In an effort to do just that, these three warriors discovered a way to shed their human bindings and ascended into heaven to fight alongside the big man himself.
Gabriel Belmont was sent by the Brotherhood of Light to find closure
The world's in a pretty rough place by the time Gabriel makes his appearance. Monsters are roaming the land unchecked, a spell prevents the spirits of the dead from leaving the Earth, and the three Lords of Shadow have never been stronger. The Brotherhood of Light sends our Combat Cross-wielding hero to find Pan, one of the old gods, who will show Gabriel how to speak with the trapped soul of his recently murdered wife Marie.
Gabriel traveled far (and killed so many werewolves) to assemble the God Mask...
To face Cornell, Gabriel travels through Agharta, a once-great city now controlled by Cornell's Lycan hordes. Along the way he teams up with Claudia, a centuries-old resident of the ruined civilization, and her golem protector. This goes well, until Gabriel murders her in his sleep, destroys the golem, and steals its cursed power gauntlet (did I mention that Gabriel has been a little messed up since losing his wife?). Gauntlet in hand, he eventually defeats Cornell's werewolf form and collects the first piece the God Mask, a holy artifact whose power could resurrect his wife.
...but Zobek turned the tables on Gabriel
After striking a deal with a disturbingly emaciated witch, Gabriel is teleported to the Land of the Necromancers. This realm is forbidden to mortals and those who are pure of heart, leading Pan to challenge an extremely distraught Gabriel in combat so that his divine blood may open the path. Exhausted and ready to tear his final enemy limb from limb, Gabriel reaches the end of his journey only to be greeted by the Lord of Death himself--Zobek. And that's where things start to get confusing.
Satan (yes, the real one) showed up, and revealed his master plan
In a stunning double bluff, it's revealed that Satan himself was influencing Zobek so that he could acquire the God Mask and challenge his father for the right to rule heaven. With Gabriel out of the way and Zobek nowhere near capable of challenging him, Satan probably would've gotten away with it too, if it weren't for that meddling Marie. Using the power of love (feat. Huey Lewis And The News)--along with the energy of hundreds of trapped souls--Marie gives Gabriel the energy to face Satan mano-a-mano.
Gabriel went full vampire to kill an extradimensional evil
But while all of this should be enough to earn an early retirement, the world had other plans for poor Gabriel (which, coincidentally, were the perfect length for some Lords of Shadow DLC). It seems the Lords of Shadow were keeping an even greater evil known as the Forgotten One under wraps in Carmilla's old castle. Sensing his return, Laura, the young vampiress, calls for Gabriel's help. The two decide that their best bet is to send the experienced demon hunter into the Forgotten One's dimension, but there's a catch--only dark beings can survive the journey.
Gabriel and his son Trevor didn't really get along
As Gabriel (or Dracula, as he's soon to be known) begins to embrace his dark side, his son Trevor Belmont walks down another path--a path chronicled in the Mirror of Fate spin-off. Born in secret before Marie's death, Trevor was raised by the Brotherhood of Light with full knowledge of his mother's murder. Once he grew to adulthood, Trevor left his wife Sypha and child Simon behind, traveling to Dracula's castle to avenge the memory of his mother.
Trevor's son Simon showed up to layeth the smackdown
Simon Belmont is adopted by mountain warriors who train him in the ancient arts of barbarian badassery. After decades of preparation, he returns to Dracula's castle seeking to end the undead mother-killer once and for all. Meanwhile, an amnesiac Trevor awakens years after his death to find that he has transformed into a vampire. He takes the name Alucard and follows Simon as he battles his way through the castle, too ashamed of his transformation to reveal himself to his own son.
Gabriel struck a deal with Zobek after eons of misery
And return Dracula has, although he seems to be a little worse for the wear. Met in the present day by an extremely well-dressed Zobek, Gabriel is grey, emaciated, and extremely bitter toward his old master. Zobek, apparently not put-off by Dracula's centuries of unclipped fingernails, informs him that another old acquaintance, Satan, will soon be making his way back to the mortal realm.
