Black Zodiac

The Black Zodiac is a dark inversion of the normal Zodiac. Like its celestial counterpart, the more eldritch Black Zodiac is divided into twelve arcane signs; unlike its counterpart, these signs represent twelve earthbound ghosts necessary to gain access to the Ocularis Infernum.

In addition to the twelve standard ghosts, the Black Zodiac also encompasses a thirteenth ghost; the Broken Heart. This spirit is the final ingredient in the spell to fully activate Basileus's Machine due to being sacrificed willingly out of an act of pure love instead of misery.

The Thirteen Ghosts
There are thirteen souls bound to earth, foretold and described in The Arcanum, which make up the Black Zodiac, and are as follows:

The First Born Son
The first ghost in the Black Zodiac. The First Born Son is the ghost of a little boy who dies of arrow shot through the head. It may possibly also represent an infant ghost or a firstborn male child. Cyrus chose the ghost of Billy Michaels as the First Born Son.

The Torso
The second ghost in the Black Zodiac. The Torso is missing his legs, and/or his waist. It may possibly represent a severed or mutilated ghost. Cyrus chose the ghost of Jimmy Gambino as the Torso.

The Bound Woman
The third ghost in the Black Zodiac. This ghost is of a woman who died having been tied-up in some fashion, but in the Arcanum, the only bound ghost is the Angry Princess (in which case, it just represents general suicide), so it is entirely possible that instead of being physically bound, this ghost had, as a prerequisite, sealed her own fate, as seen by how some sort of action, such as her infidelity, led to her demise. Cyrus chose the ghost of Susan LeGrow as the Bound Woman.

The Withered Lover
The fourth ghost in the Black Zodiac. This ghost is of someone who died having a withered or worn appearance, it may also represent someone (the prerequisite may be that of a woman) who had her future, dreams or relationships destroyed or broken, like being separated from one's mate. Cyrus chose the ghost of his niece-in-law, Jean Kriticos, as the Withered Lover.

The Torn Prince
The fifth ghost in the Black Zodiac. This ghost has much of the skin on the right side of his body missing, leaving the bones and muscles exposed, it possibly represents a "prince" (spoiled, popular, loved, etc), who's pride was taken down, or had his ego destroyed, (hence the "fallen hero" statement seen in his story). Cyrus chose the ghost of Royce Clayton as the Torn Prince.

The Angry Princess
The sixth ghost in the Black Zodiac. This ghost apparently is of a young woman who dies by committing suicide and, as the name suggests, is that of a woman, either popular, spoiled or beautiful (just like that of a princess) that couldn't see past her privileges and, as such, she would be unhappy with her blessings. Cyrus chose the ghost of Dana Newman as the Angry Princess.

The Pilgrimess
The seventh ghost in the Black Zodiac. It appears to be the ghost of a female pilgrim or a primitive woman. It may also represent an outsider or stranger, not appreciated or accepted by others, seeing the implications of her alien origins. Cyrus chose the ghost of Isabella Smith to serve as the Pilgrimess.

The Great Child and The Dire Mother
The eighth and ninth ghosts in the Black Zodiac. The Great Child is the ghost of a very large and overweight child, and the Dire Mother is that of a very small woman. They probably are ghosts of a child, spoiled even to its maturity, and a mother bad enough to let it happen. They may also be the ghosts of a related mother and child. Cyrus chose the ghosts of Harold and Margaret Shelburne as the Great Child and the Dire Mother.

The Hammer
The tenth ghost in the Black Zodiac. This ghost is that of a muscular, heavy-set blacksmith who wields a large hammer. Any further or deeper implications are unknown. Cyrus chose the ghost of George Markley as the Hammer.

The Jackal
The eleventh ghost in the Black Zodiac. The Jackal is the ghost of a disheveled man wearing a cage on his head, which probably represents bestiality or wildness, seen as how much of a savage and of how aggressive the ghost is, as well as his depravity and sexual implications. Cyrus chose the ghost of Ryan Kuhn to serve as the Jackal.

The Juggernaut
The twelfth ghost in the Black Zodiac. This ghost is that of a tall, ugly and incredibly-strong man. Cyrus chose the ghost of Horace Mahoney to serve as the Juggernaut.

The Broken Heart
The thirteenth and final ghost in the Black Zodiac. This ghost dies by leaping into the core of Basileus's Machine out of an act of pure love. Cyrus chose his nephew, Arthur Kriticos to serve as the Broken Heart.

Trivia

 * A traditional zodiac is composed of twelve signs, not thirteen.
 * In the remake, despite being killed, Dennis Rafkin isn't part of the Black Zodiac.