ESP stands for Extra Sensory Perception. Cause of gaining ESP is currently unknown in our time.
In Two Clusters, there were a fairly large number of ESPs. On year 9599 alone, number of registered ESP exceeded 50 million although this number included class B, C, and D.
There had been few hypothesizes about the increasing number of ESPs. The most convincing one had been a hypothesis that gravity may have something to do with ESP as those who were born in low or zero gravity had a relatively higher chance of being an ESP.
However, some of the most powerful ESPs in the history of Two Clusters were born under a normal gravity level ( 1G ).
There are 5 ranks for determining ESP's ability.
Rank S is the highest. Then rank A, B, C, and lastly D.
There were two kind of ESP.
One was active ESP. The other was passive ESP. Active ESP was just that. They were active ESP users. Active users were able to manipulate their powers at will. Whereas passive ESP could not control their powers. Instead, their powers existed in a form of aura and was constantly being radiated.
A good example of a passive ESP was Roon Dietrich whose passive ESP was her voice. Her voice had a soothing effect. She did not control her passive ESP. Active ESPs were far more common than passive ESPs. However, it must be noted that passive ESPs were often hard to distinguish because they were often not aware that they were indeed passive ESPs. Most of passive ESPs lived normal lives and never realized that they were ESPs.
Higher tier ESPs, such as class S & A, often specialized in something, an element or sometimes something very unique and awkward.
Specialization of class S ESPs were quite often unique. Marat was a class S ESP with a unique specialization called "Clarity". Lila (Lilicious)'s specialization was " transmutation". Cecil Klisis' specializations were "time" and "space" and "blood".
In class A ESP's cases, specializations were often cosmetic elements: fire, water, earth, wind, lightning, and so on.
Extremely rare cases of ESP. The most class S ESPs ever existed was between 85xx to 97xx. However, the number never exceeded ten at once. However, it must be noted that not every ESP was able to go through proper testing examinations. Therefore, it was feasible that there might have been more who were not registered.
More likely, however, if one was a class S ESP, people around him/her would notice sooner or later.
Class S was determined when one's ESP powers were well ESP beyond score charts. In some cases, class S ESPs were treated as human treasure, for they were capable of seemingly impossible. Class S ESPs had a strong tendency to possess often very awkward personalities which allowed them to act more like villains than heroes. Such examples were Cecil Klisis, Sae, Juron, Aedy Freedom, and so on.
Masu the sage, explained why it was so. He once said, "Class S ESPs can often foresee into the future. It is not their power however. They are able to predict because they are too smart. When you know too much about how something will end exactly, you can't act like a hero."
A much more common class ESPs that were found in Two Clusters. Many great heroes were class A ESPs. Shell of Pluto was a class A ESP. Gair was a class A ESP. Like class S ESPs, class A ESPs often possessed specialty. The most common specialties were cosmetic elementals (Fire, Water, Earth, and Wind).
Weaker than class A but stronger than class C. Class B ESPs were the workhorse of elite forces. They were very often hired by government agencies to become either agents or elite soldiers. Some of them had a specialization which enables them to reach prowess of class A ESP in their specialization.
No class C ESP had a specialization. They were very weak ESPs. Unlike class B ESPs, they didn’t always get hired by government agencies. When they did get hired, they were usually stuck with basic tasks. Most of class C (and D) ESPs led normal lives.
Class D ESP was the most common ESP and the most useless ESP at the same time. What a class D ESP was capable is very little. They might be able to see through a deck of cards. That was pretty much it. Some of them would work in entertainment industry as magicians.
Overexerting for ESPs had dire consequences. But in return, it'd grant an ESP ten times more powers than they normally would. When an ESP overexerted, the first symptom was bleeding from nose, ears, and eyes (bloody tears). A short while later, face would become bruised. (This symptom did not happen to all ESP who overexerted.) An overexerted ESP, at this point, would normally become unconscious. This was the crossroad for ESPs. Some would die. Some would survive.
An ESP (Class C+) could easily live well past 600 years old, provided that they didn’t get killed in action during their lifespan. The average lifespan for ESPs was 800 years old. A few lived past 1,000 years old.