For Ellis, the super violent nature of the show serves as a tool to help establish the series' main protagonists. Trevor Belmont (Richard Armitage) is the weary descendent of a monster-hunting family who only cares about placing his next drink order. He's burned out on the idea of being a hero for others but a run-in with an order of clerics leads him to Sypha (Alejandra Reynoso), a mage who has her own disdain for the Church, and Alucard (James Callis), a fabled "sleeping soldier" who happens to be Dracula's half-breed son. Their team up feels rushed as it's only fully realized in the season's final moments, but Ellis's wit makes it work through fight scene quips and debates about personal beliefs. One minute Trevor is in an arc of resurrecting his family's honor, and the next he's mocking Alucard and chastising him for being a "floating vampire Jesus".
For what it's worth, Ellis' script work is Castlevania's greatest strength. The show's four-episode run is lined with gorgeous Symphony Of The Night imagery and stylish fight scenes that contend with One-Punch Man and Ajin: Demi-Human, but its viewpoint on religion amplifies every gothic undertone. In Wallachia, the Church is the authority. It prioritizes faith above all else and with the help of an unnamed Bishop, it eradicates those that pose a threat to its policies and devotion to maintain control. The Church's role was short-lived but its values contributed to one of the most memorable dialogue exchanges of the season, in which the leader of Dracula's demon army confronts the Bishop about his hypocrisies and devours him in his own place of worship.
Demon: Your God knows that we wouldn't be here without you. This is all your fault, isn't it?
Bishop: She was a witch!
Demon: Lies? In your house of God? No wonder He has abandoned you. But we love you.
Demon: We love you. We couldn't be here without you. Let me… kiss you.