George Markley was an honest, hardworking blacksmith, until a man named Nathan wrongfully accused George of theft, and threatened to banish him from the town they lived in. 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 death 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, slowly killing him.
Then, as a finishing touch, they cut off George's hand, and fixed George's sledgehammer in its place.
Following his death, George's spirit remained bound to earth, and was subsequently captured by Cyrus Kriticos to become The Hammer. The Hammer was then moved to the basement of Basileus's Machine with the other eleven ghosts.
When Dennis and Maggie pass by the Hammer's containment cube, he slams at the glass with his sledgehammer, spooking Dennis. The Hammer is the tenth ghost to be released. He pursues Arthur and Kalina through the basement, but the two narrowly escape from him up into the house.
Later, he attacks Dennis and Arthur in the basement. While Dennis traps Arthur behind a glass pane, Dennis keeps The Hammer distracted until The Juggernaut arrives. The Hammer is able to beat Dennis to the floor before The Juggernaut finishes him off.
The two ghosts then turn their attention to Arthur, but he is protected from them by the ectobar glass pane, so they can't get to him. A Latin chant then causes the two, along with the other ten ghosts, to go to the center of the machine and power it up.
When The Hammer and the other ghosts are freed from the trance, they throw Cyrus into a rotating crest of rings. The house then explodes, destroying its walls, and freeing The Hammer and the other eleven ghosts.
- Hammer: In his ghost incarnation, his hammer replaces his left hand, which he uses with lethal force.
- Spikes: Shown removing one of his railroad spikes from his body, it is implied that he can use these as weapons.
- The whispers which signal The Hammer's approach are deep growling.
- The Latin inscription beneath The Hammer's symbol in The Arcanum, "Malleus Ignis", translates to "Fire Hammer".
- His ghost file is represented by railroad spikes.
- He's the only African-American ghost in the zodiac.
- It was unknown what the false theft was about.
- Is considered the most understandable of the killers, as the law was corrupt and the people he killed were his family's murderers.
- Although he was capable of removing his railroad spikes from his body, it is unknown if he could use them violently, as he is seen using his hammer hand.
- According to Howard Berger, the special makeup effects artist, initially the Hammer's makeup took approximately 4 hours to apply, but eventually, the team was able to get it down to approximately 2 hours.