World of Sorrow 1; The Demon Dilemma by Kelvin V.A Allison

Even the things that go bump in the night have to answer to somebody...

What starts out as a routine investigation for Agent Victor Sorrow of the Occult Creatures Licensing Division soon spirals out of control when a bane demon is released upon an unsuspecting England.
As he tries to solve the case with his partners Agent Pinder; a womanising conjurer and Agent Letterman; a junkie empath, he also has to contend with his Ghoul boss who hates him, a female werewolf who hates him even more and a traitor in their midst...all the while trying to stop the demon in his own soul from taking control.