The Chasing of a Silver Bullet

Detective Lucas Angel deals in cases that don't exactly meet the norm.
As a private investigator, Lucas has seen many a strange thing and witnessed phenomena that would leave most people either perplexed or seriously disturbed.
Along with his "brother"; and entity known as the Dark, they solve cases most people won't - or refuse - to solve.
But now, Lucas faces yet another case that makes him question himself, and the way he deals with his gifts.
Most times, he deals with monsters and demons - both real and figurative .
But when he has to deal with a man that wants to be rid of his own monster, leaving Lucas with a dire question:
At what point do the man and monster meet? And which has dominion?