After forming a preliminary idea, Schiller began experimenting almost without pause. To ensure the experiment's safety, he did not leave Xavier's School for Gifted Youngsters and instead stayed with Professor X, so they could pull back from the brink if anything went wrong.
Gray Mist quickly altered the magnetic field around Schiller as he requested. At the same time, another personality besides Greed, who was controlling the body, surfaced.
Normally, there would be two possible outcomes. If Greed willingly clocked out, he would be replaced, and another personality would take control of the body. But if the personality currently controlling the body was unwilling to return to the High Tower, the other personalities could not come up.
This time, however, Greed experienced a different sensation. He felt like the water at the end of a pipe. When the faucet opened again, he could seek another place to dwell instead of having to remain inside the body.
Following that feeling, Greed's ghost successfully separated from the flesh. According to Professor X's observation, it had been retuned into a mutated soul—the so-called ghost.
During the following experiments, Schiller discovered that this ability was not nearly as convenient as it seemed. It came with all sorts of limitations, and he also found a very peculiar phenomenon: pathological personality traits were better suited to becoming ghosts, and became stronger after doing so.
Schiller and Professor X discussed this point. The two top psychologists believed that terms such as "vengeful ghosts" and "wrathful spirits," which had existed since ancient times, were not without reason.
When humans experienced extreme emotions, their brain waves changed. Based on Professor X's observations over many years, extreme negative emotions were more powerful than extreme positive emotions, and caused more drastic changes in brain waves. In other words, emotions such as