Chapter Text
Leon Belmont, a knight of the Catholic Church, returns home to France from the Crusades with his friend and battlefield companion Mathias Cronqvist of Wallachia, who discovers that his wife Elisabetha has been killed by a plague. Months later, Leon's betrothed Sara Trantoul is kidnapped by a demigod Scion of the God of Blood Zalmoxis, Walter Bernhard. At Mathias' urging, Leon tracks Bernhard down to his castle in the Terra Incogniae known as the Forest of Eternal Night, where Bernhard plans to ascend to godhood by constructing the Mantle of 'Lord of Darkness' by binding monsters and creatures of the night from various Pantheons into his service through the use of a Relic known as the Ebony Stone.
With the aid of an alchemist known as Rinaldo Gandolfi, Leon tracks down and kills the five guardians of Bernhard's castle (a Constructed life form from the ‘Hollow Earth’ Terra Incogniae known as Agharta, the undying Gorgon Medusa, an Undead Parasite corrupting the castle, a Succubus summoned from Hell, and Bernard’s vampiric childe Joachim Armister, imprisoned for rebelling against his sire) and the Forgotten One, a Titan that had once threatened Zalmoxis, and which Walter is using to power his ritual.
With the power of the castle severely weakened Leon finds Sara, only to discover that, in a twisted act of sadism, Walter has Turned Sara into a vampire. Unwilling to live in undeath and knowing that the alchemical whip Rinaldo is constructing for Leon requires the willing sacrifice of a vampire to complete it, Sara begs Leon to strike her down, in the process creating the ultimate weapon against all creatures of the night - The Vampire Killer.
Now driven by both revenge and a desire to ensure no other people suffer his loss, Leon tracks down Walter Bernhard, slaying him with the Vampire Killer. As Walter dies the being known only as Death, the living incarnation of humanity's fears of The Coming End That Waits For All And Cannot Be Ignored, appears for his soul, along with Mathias Cronqvist, revealing that almost all of the events that had taken place were part of Mathias' plan to revenge himself on the Christian God for the death of Elisabetha. Indeed, it was Mathias who convinced Bernhard to capture Sara, knowing that Leon’s force of will would carry him through the castle to depower Walter just enough for Mathias to land the killing blow.
Capturing Walter's soul inside the Crimson Stone, a twin Relic to the Ebony Stone which allows the wielder to control Death itself, Mathias completes his plan, combining the two Stones and claiming all of Walter's Legendary Titles, his place as a Scion of Zalmoxis, and his curse of vampirism. He offers to let Leon join him in this new cursed existence, but Leon refuses, and proves his resolve and lack of fear by slaying Death, although Mathias himself succeeds in binding himself to the castle, completing Walter’s plan in the process and ascending to the Mantle of Lord of Darkness.
Shocked and betrayed by what his friend has become, Leon flees from the newly named Castlevania, vowing to always stand in Mathias' way for as long as both the vampire and the Belmont line live:
'You have become an unclean thing, and I will never forgive you. My descendants will hunt you, even across the World if need be, until you and all like you are destroyed. From now on, the Belmont Clan shall hunt the night!'