These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Castlevania III Draculas Curse
Ensemble Darkhorse: Alucard was a relatively minor character in this game, but he evidently had enough of a fanbase to later become the main character of Symphony of the Night.
Fridge Brilliance: This game is widely considered the hardest games in the series. It is said that the Belmont clan grows stronger with each new generation, and Trevor was the first to face Dracula (long before a parade of "the REAL first Belmont" Ret Cons started filing in), ergo the weakest Belmont to fight him.
Put on a Bus: Grant and the DaNasty family, besides brief mentions and doppelgangers and his drastically (unneeded and unexplained) redesigned appearance in Judgment. The DaNasty family has never appeared in the proper games since Dracula's Curse. Hell, even Dawn of Sorrow has a mode where you can play Alucard and descendants of Trevor and Sypha.