So, I just beat the game, but one of the things I'm wondering is about Zobek. In the Bio it says that Zobek is a warrior in the Brotherhood of light, but we know that Zobek is actually Death in disguise. But they refer to him as Zobek, even though he just took Zobek's shell and is not actually Zobek right? 
 
So Zobek must have been dead, and then Death took his dead body and animated it by using that other mask (I have no idea what that mask is either) and becoming him. Or was Zobek alive all this time? Because his Bio never really states if he was dead or alive. 
 
Or was Death ALWAYS Zobek, hence him being alive in modern times as well?

Konami definitely got bored of writing the story towards the end of the game, the story basically commits suicide. Why did Satan randomly appear? Where did the evil mask come from? and after the credits, why is zobek still there? Stupid ending.

" @dumplingdinosaur: I think the ending was brilliant and I for one didn't see it coming. I mean honestly did you know Gabriel was going to end up becoming Dracula? "

Death is basically a Necromancer who delved into deeply forbidden witchcraft and thus finds a way to cheat and ultimately govern death. It's interesting seeing this (previously poorly explained) character get a back story that actually kind of makes sense in that universe. In a way, Death/Zobeck shares more in common with Shaft then the Death incarnations in previous Castlevania games
  
In the other Castlevanias, I just thought he was some divine being like Satan and just decided to chill with Dracula for a bit.

" @dumplingdinosaur: Satan was the mastermind behind the whole plot, and it gives the second game a villain, thats why they put Satan there. Also it gives a reason for Zobek and Gabriel AKA Eu sunt Dracul AKA Dracula to team up together.  You know, how in every other Castlevania game, Death is Dracula's right hand man? Isn't that awesome? I guess you have to be a fan of the other Castlevania's to get what they were going for there though.  But the whole thing goes along tiers. Satan and God are at the top, while the three Lords of Light and Lords of Shadow are next, then people. Zobek tricked Gabriel, but the idea what implanted in his head many many centuries ago by Satan who was waiting for Zobek and to catch him off guard. He finally does when Gabriel is saved from death, then Satan takes his chance. He just didn't think that Gabriel would stand as much of a chance as he did.  I think the ending was brilliant and I for one didn't see it coming. I mean honestly did you know Gabriel was going to end up becoming Dracula? "

As far as i could follow the story; Zobek was one of the Lords of Shadow and when he went to heaven with the other two his darkside stayed behind and became the dark lord of death.  
  
The Satan plot twist that followed was something that no one was expecting because you couldn't know. I still thought the scene in present day (?) was pretty cool. And it makes me wonder about a sequal. I sure hope the game does well enough to get a sequal; i loved it all the way to the end.