Oh great, he's started VMing me. Better not add fuel to the fire. >_>
No, the soul devouring demon is something else. It is the Old One, a demon placed in this world with an insatiable thirst for souls. It's cries for souls to feed on, resemble that of a pathetic child. The lore of this game goes pretty deep (if you choose to dig for it that is) and it is a very dark game. Dark Souls even more so.
PS: that dragon like creature is the Dragon God. And yes, he is every bit as intimidating as he sounds...