Why the Darkness?

Because there are times, no matter what you do, you're screwed.

Jackie Estacado is a bastard from a long line of bastards. He grew up hard and mean, was a killer before he was legal, and was Don Franchetti's number one hitman by the age of 18.

He was also born into one hell of a curse. See, on said 18th birthday, Jackie became the next in line to host the immortal Artifact known as the Darkness.  It has been at war with the Angelus since Creation, and is the embodiment of the original Chaos that existed before.  The Darkness is passed on from the father to son as the son is conceived, killing the father to sleep within the son until the host is of age.

Which brings us to Jackie. 

Jackie has used his dark powers to climb the ladders of the criminal underworld in a trail of horror and bloodshed.  He killed his patrón (who had murdered his girlfriend, by the way), as well as anyone who stood in his way, established his reputation as a violent and ruthless murderer with the help of his minion-like Darklings, and even established a drug cartel after taking over the small island nation of Sierra Muñoz.

The Darkness also has a "one foot in one world, one foot in the other" complication.  The Darkness mated with the Angelus to créate the powerful Witchblade, a supernatural weapon that chooses its own female host to act as balance between the two.  This brings Jackie into a cosmic war that threatens to bring the universe to an early end if all 13 Artifacts are ever brought together.

And of course, a weapon this powerful also has a weakness - it can't work in the light, but can manipulate the shadows to créate a carapace-like armor, Darklings, tentacle/blades, even sentient slave creatures.  It can give Jackie anything he wants, which makes it Top Cow's ultimate monkey's paw:  be careful what you wish for...

You just may get it.