Good to the Last Drop by Declan Finn

The final war begins.

Merle Kraft, Marco Catalano and Amanda Colt have battled against the mythical Council, a supernatural conspiracy that monsters fear. This war has brought them up against vampires, minions, and demons from Hell.. Along the way, they have accumulated allies among the police, the military, the mafia, college students, lowly street gangs, and even other vampires. Marco and Amanda have overcome their biggest terror – their passion for each other.

But now, they face the final threat, one that is the culmination of every threat before them. This creature from Hell has powers beyond anything they’ve ever seen before, and has allies of his own: including SpecOps minions, an army of vampires, and packs of werewolves.
And that was before Marco got bitten.