Castlevania, as most probably know by this point, is a series of videogames that began in 1986 with the release of the first game in the series, aptly named Castlevania, on the Famicom Disk System in Japan before being ported to the Nintendo Entertainment System in North America one year later. Since then, the series has expanded to include twenty-nine games and is still going to this day. Then in 2017, to the surprise of everyone, streaming service giant Netflix unveiled to the world their brand new Castlevania animated series produced by Frederator Studios and with famed comic book author and screenwriter Warren Ellis as the creative brains behind the project.
The series ran for four seasons and turned out to be a massive hit, owing to Warren Ellis' clever writing and well-known actors such as Richard Armitage and Graham McTavish in leading roles. Because it was such a hit, of course, there would be a demand for more, and Netflix was more than willing to provide.
In May 2021, Netflix announced that a brand new Castlevania spin-off series was already in the works. It would focus on Trevor Belmont and Sypha Belnades' descendant, Richter Belmont, and be set during the French Revolution. Much like Trevor before him, with twenty-nine games in the series, there is a plethora of source material that Netflix can pull from as far as where Richter's story could go, but will the series end with him. Many other members of the Belmont family line have had their time in the spotlight, some for longer than both Trevor and Richter put together. In theory, Netflix's Castlevania could go on for as long as there is a Belmont with a story to tell, but how long should it go on? If one were to delve into the lore of the Castlevania games, they would find that that question has actually already been answered.
Too Many Belmonts
With twenty-nine games in the Castlevania series, most of them being their own original stories with their own protagonists, as direct sequels are rare in the Castlevania series, there are many known Belmonts. Some of the more famous members of the Belmont family line aside from Trevor and Richter include Simon Belmont, the protagonist of the first two games, Leon Belmont, who began the Belmont family line, Julius Belmont, who finally killed Dracula for good in 1999, and Gabriel Belmont, the protagonist of the recent Castlevania: Lords of Shadow series.
With so many Belmonts to choose from, it is a wonder that Netflix decided to jump from Trevor straight to Richter, as there are many Belmonts in between them. Simon Belmont, for instance, is canonically Trevor and Sypha's son, so continuing the story with him would have seemed the most logical. Regardless of which Belmont takes center stage, however, their story will have to end at some point.
Being an animated series, it is, of course, very plausible that the events told in said series will not directly mirror those of the games. Like most long-running video games, some Castlevania games are better written than others. Something worth asking is that if the animated series is jumping from Trevor straight to Richter, how many other generations of Belmont's could be skipped? Trevor's story took four seasons released over the course of five years to tell, and it is reasonable to believe that Richter's story may take a similar amount of time to tell. If it takes that long to tell the story of one Belmont, Netflix will obviously not be able to tell the story of every Belmont, meaning that they will have to pick and choose which stories to tell carefully. However, even if that is the case, there is canonically a definitive ending to the fight between the Belmont family and the vampire Dracula.
The End of the Feud
According to the Castlevania canon, Dracula may always come back to life after being defeated, necessitating another Belmont to come around and kill him again. Dracula was finally defeated for good with no resurrections by Julius Belmont in 1999. This event was known in-universe as the "Demon Castle War" and is unfortunately not directly shown in any game yet. The first notable reference to these events happened in 2003's Castlevania: Aria of Sorrow, where the player character, Soma Cruz, can encounter several characters that participated in that battle, including Julius Belmont himself, following an instance where he lost his memory and needed to regain it.
Because the events of the Demon Castle War are not directly shown, however, all that means is that Netflix and Warren Ellis (assuming he stays on board for the whole thing) have more creative freedom regarding what to actually show for the events of that battle. Regardless, if there is a definitive, canonical ending to the battle between the Belmont family and Dracula, it is the Demon Castle War. If there were any place to end the Castlevania animated series, it would be there.
After the events of the Demon Castle War, the series begins to focus less on the Belmont family and Dracula, so there would be little reason to tell those stories unless fans absolutely demand it.