The series steadily improves as each season unfolds. The initial set of episodes felt a little sluggish, mainly because there were only four of them. Season 2 became engaging, culminating in a large-scale showdown featuring the three protagonists against Dracula! Season 3 proved to be quite strong, although the final episode ended on a rather depressing note, with each character’s situation; it's like every time you think things might get better, you’re let down by a grim illustration of what people are capable of. Castlevania, even though it originated from a well-known video game, strikes me as an animated version of Game of Thrones—but with vampires involved.

Source on TMDB