The Maleficient seven - Cameron Johnston

When you are all out of heroes, all that's left are the villains.
Black Herran was a dread demonologist, and the most ruthless general in all Essoran. She assembled the six most fearsome warriors to captain her armies: a necromancer, a vampire lord, a demigod, an orcish warleader, a pirate queen, and a twisted alchemist. Together they brought the whole continent to its knees... Until the day she abandoned her army, on the eve of total victory.
40 years later, she must bring her former captains back together for one final stand, in the small town of Tarnbrooke - the last bastion against a fanatical new enemy tearing through the land, intent on finishing the job Black Herran started years before.
Seven bloodthirsty monsters. One town. Their last hope.