Sagitanas

The creature known as Sagitanas is an ancient force of wrath, whose appearance throughout the millennia in which he's existed has always been marked by excessive bloodshed, brutality and vendettas. As a Wrath Daemon of fearsome power, Sagitanas has lead many an unwary mortal down the road to ruin.

Of particular note is how the devil appears to take a perverse delight in entering the lives of young children, usually after devouring their family pet; which he then subsequently replaces, the demon then begins to systematically drive the young child down the road of sociopathy. Talking sweetly to them at night about the joy of murder, especially the murder of the people closest to you. It's no surprise that the first victims of Sagitanas' proteges tend to be their own parents or siblings (in some cases he's even inspired siblings to kill one another for it's approval).

This was how it was when a young girl named Rosa Abatangelo got her first pet, a doberman she named Spots, which to this day is Sagitanas favored form; which he usually appears in, only assuming his true monstrous form. Allegedly, there's been many "Spots" through the years, with the dogs death having been faked multiple times, as Sagitanas uses his shapeshifting powers to make each incarnation of "Spots" different from the previous one. No one would ever suspect that each dog was merely Sagitanas assuming different forms.