Most people thought that half ghosts were simply that, half human and half ghost. In reality they are so much more than that. They are living, breathing Genius Loci. They allow both humans and ghosts to feel stronger and sharper. They are powerful, immortal, and dangerous, but the worlds would not be the same without them.

First came Ambition, cunning and ruthless clothed in white with black hair that curved into wicked horns, he sought to devour everything and possess that which was out of his grasp. Twenty years after, Soul was born to counteract the hunger of Ambition. He was young, but strong, with piercing green eyes and snowy white hair. His one desire was to protect the innocent and lead them out of darkness. The next created were his companions, Art and Innovation, both of which were brought into being by the actions of other spirits. Unlike her violent stepfather, Undergrowth, Art could harness nature's own beauty to inspire ghosts and mortals, and the combined efforts of Desiree and Technus meant that Innovation had to merely imagine a new device to make it part of reality. Even Soul's older sister became the muse Philosophy when she faced down the mad mortal Freak Show to defend her brother.

Later on Ambition's meddling would create the final two muses, Strategy and Music. Music was an innocent child that Ambition had created as a muse using the DNA of Soul and Art, but they readily accepted her as their daughter and made sure that she was well protected from Ambition's plots. Strategy, however, was a warrior dressed all in red that staunchly supported Ambition until he revealed his true nature to her. She had already become a muse and was frightened and confused by her power until Soul and his family took her under their wings and guided her out of the shadows.

Soul was indisputably a leader to most of both worlds, carefully settling disputes and ending invasions before they began. His friends became his family as he drifted apart from his parents, settling into the position of Soul without taking advantage of it. Life became good for the six Phantom Muses, so called because Soul was also known as Phantom when he took ghost form, and in the peace they began to let their guard down. Unfortunately, Ambition was waiting to strike.

Ambition was not content to let Soul have the respect and power that he felt rightfully belonged to him. In his jealousy, Ambition betrayed both Earth and the Infinite Realms by releasing the tyrant Pariah Dark from his sarcophagus. At first it seemed that Ambition was an equal to Pariah and the Fright Knight as they used their cunning and skill to trap one muse after the other in prisons specially made for them, but the tables were quickly turned on Ambition as he was stripped of his power as a Muse and enslaved to Pariah.

As the vibrancy of the Muses' rule faded to gray and Pariah conquered both dimensions Clockwork, the master of time, had no other choice than to freeze time in both worlds. All beings still moved and lived their lives, but they were un-aging and undying, without inspiration or free will. Both the living and the dead were hollow shadows of what they once were and there was no hope of freedom for either.