>>> This is my first Castlevania game and WHAT A GAME!

Anyways, after play and beat it with about 194%, there are some questions in my mind, since I know nothing about the previous games and story this ones may sound stupid for the fans.

At the begining you play with Richter belmont and defeat Dracula..
This is supposed to be the ending of another castlevania game,
which game is it??
I`ve heard its Dracula X but Im not sure.

While you are fighting dracula with Richter a little girl appears and restore your HP.
Is this girl Maria???

If I remember well, Richter said that Alucard fought alongside another Vampire hunter in the past..
This means there is another Castlevania Game with Alucard on it??..

Was Alucard`s mother human?? and why she was killed by humans??

Why alucard side with humans?
wait I think I already know this one..

Is Shaft the guy who always try to resurrect dracula or this is his first appearance??

and the final, this game is an RPG right??