Ehh,
I know it was mentioned, and I know its been a referenced Anime trope...and I will say its /Catholic/ depictions not /Christian/ but then we end up in the Catholic v orthodox v protestant thread..
BUT...
In Castlevania universe, Belmont's have been always a religious link, and a positive one. Even if this is only to pay heed to Brham's Dracula origin that IS Dracula's origin because Lament of Innocence is still cannon in game and anime. Dracula became Dracula after being a "Man of God" and then did such a dramatic 180 that his curse against God was so much of a shift it was /nearly/ the same as Satan betrayal. Lord of Shadows not withstanding.
So, the counter has always been "true" religion, GENERALLY represented in the Belmonts - heck Simon buries and prays for Dracula at the end of CV2.
Items are pro-religion, holy water, holy rain, crosses etc. even if this is "vampire tropes" - it is "Castlevania" and not fully in alignment with the standard anime trope in their odd views of western religion.
This is also why I did not like the change in the anime from, I think S1 to S2, or S2 to S3 - I forgot exactly when... I think it was 1.
The setup was defending the town, the "priest" that was obviously evil, stays in the church and abandons the town - Belmont and co are there to defend it, but cannot do it alone - they needed help- and that came from a lone devout monk to make the holy water - while in contrasting the evil priest figured he was "safe" in the church and by /his role/ - while that proved absolutely false and he got eaten while, the devout /true to God/ humble Monk was successful in making holy water that WAS affective.
and that leads to why I HATED that an undead, mind controlled, evil priest (I think it was the same character) was able to just go make the entire river holy water, after explicitly showing (by way of the ending where he got killed) that his false religious 'powers' were nothing. Sure it made a good scene THEN, and was a pivotal tactical move- but imo broke and destroyed the ending of the past season showing the power of God and true believers vs. the arrogant man-god religion used for men's selfish desires.
So... Castlevania imo does not fall within the standard anime tropes of being Western Religion (Generally Catholic in portrayal) is evil/false/useless/bad - so the bullet point, again, imo, stands.