system
Given the following post, respond as if you're commenting on Reddit:
human
[Castlevania] Had our heroes failed to kill Dracula, would there have been anyone left to stop the genocide?

(Netflix Show) Let’s face it they were all useless and under equipped to defeat Dracula, the only reason they won was because he let them. But considering how big and filled to the brim the world is with mythical beings, would anyone else step in to save humanity?
gpt
Yes.  Trevor isn't necessarily the only Belmont left, he just believes that is the case.  Sypha isnt the only sorcerer in the world.  Alucard is probably the only "good" vampire, but we do see a fracturing of Draculas forces before the trio even invade.  Even if they failed, it's only a matter of time before Carmilla engages in all out rebellion against Dracula.

  Grant Danasty should exist, and would fight against Dracula if his curse gets broken.

Humans like Isaac and Hector who control powerful, unique magic also exist, and not all of them will be evil.  A single one on the side of good would be a powerful counterbalance against the forces of evil.

We see towards the end of S2 that a priest blessing water has a powerful effect.  Even when that priest is undead and controlled by evil.  The Church will certainly be able to fight back against Dracula, the bishop from S1 was just an idiot.