In Castlevania III, you run across these helper characters that you can take along on your journey to put the beatdown on Dracula. The thing is, though, that you have to choose the correct path, and they're pretty deep into the game.
But you can bypass all of that.
When you start the game, at the Name Entry screen, if you put in this name.
You can start with Grant as your partner
If you put in this one
You start out with Sypha
And if you put in this one
You start out with Alucard
Of course, this keeps you from getting lots of free lives, so you'll have to decide whether or not the trade-off is worth it to you.