saragoss
If you ask him, Saragoss will say that he is one of the Old Ones, that he has been around since the Creation of the Void.  But he's bragging.  He hasn't been around that long.   He's powerful and old, yes but not as old as Creation. 

And if he was as powerful as he thinks he is, he wouldn't have been bound to Tarken's Mill by a mere human.  Even one as evil as Tarken Marsten.

When Tarken Marsten first came to Maine, he discovered Saragoss' temple in the area that eventually
became Tarken's Mill.  Using secrets that he had gathered over the years, Marsten managed to bind the Demon to the area.  He then used the power of the Demon for his evil purposes and lengthen his life.  He sacrificed some of the settlers of the area to Saragoss to try to appease his prisoner. Within five years,Saragoss was able to break the spell of control that Marsten had on him and kill him.  Saragoss still wasn't able to escape his prison due to the runes that were placed around the temple.  Saragoss took the form of his captor as a reminder of his imprisonment.

Knowing that the Sword of Gwydion will help break the enchantment, Saragoss sent some of his zombies to steal the Sword when it was scheduled to be displayed at the Museum in Tarken's Mill.  Unfortunately for Sargoss, the Sword choose a Champion before it could be stolen.
After centuries in captivity, Saragoss has gone crazy and only wants one thing: to be free to destroy the town that his captor created and from there to take over the world.  His power to create and control zombies will allow him to create a vast army.

Recently, the Champion, Jason Masters,discovered that Saragoss may succeed in his attempt to escape his captivity.  In a possible
future Saragoss escapes and his zombies take over the East Coast of the United States.  He also attempts to raise one of the Old Ones to destroy the world. 

Jason was able to stop the event that lead to there being no one to prevent Saragoss's escape.  Now the Champion and his friends have to make sure they can stop Saragoss in this timeline.