The Hammer is the ghost of George Markley, and the tenth ghost in the Black Zodiac.
George Markley was an honest, hardworking blacksmith, until a man named Nathan wrongfully accused George of theft, and threatened to banish him from town.
Knowing he was innocent, George stood up to Nathan and refused to move, causing Nathan and his gang to one day beat George's wife and children to death.
Enraged, George tracked down Nathan and his friends, and brutally beat them to a pulp with his sledgehammer.
When the town discovered what George had done, they dragged him back to his shop where they tied him to a tree and drove railroad spikes into his body with his own sledgehammer.
Then, as a finishing touch, they cut off George's hand, and fixed George's sledgehammer on in its place. It was a grave mistake that would make George's ghost a very brutal and dangerous one.
Following his death, George's earth-bound spirit was captured by Cyrus to become the Hammer.
The Hammer was then moved to the basement of the house.
Later, he attacked Dennis and Arthur in the basement. While Dennis trapped Arthur behind a glass pane, Dennis kept the Hammer distracted until the Juggernaut joined in, and the Hammer was able to beat Dennis to the floor before the Juggernaut finished him off.
The two ghosts then turned their attention to Arthur, but did not try to attack him as the ectobar glass pane would protect him.
A Latin chant then caused the two, along with the other 10 ghosts, to go to the centre of the machine and power it up.
When the Hammer and the other ghosts were freed from Cyrus's trance, they threw Cyrus into a rotating crest of rings.
When the house exploded, destroying its walls, all twelve ghosts escaped the house and into the woods.