Empathy or Emotional Perception is the mental ability to feel or experience the emotions of others. One could use this to figure out how someone is feeling, to understand why someone does what they do, etc. This can be used to determine the presence of hidden subjects as well, because the user can sense the presence of emotions, and trace them back to their source (this is called Empathic Tracking). However, sometimes the user can also (or only) project his emotions onto others, to get them to feel as he feels (this is called Empathic Projection), or gain psychic control over subjects emotions and actions after empathic and/or physical contact (this is called Empathic Manipulation).
Should the ability develop, the user might even be capable of seeing peoples hopes, fears, desires and thoughts by connecting with them on a deep empathic level
Empathic Power, also called Empathic Force or Empathic Influence is the psychic ability to affect nature and ones surroundings based on ones emotions. The user may have Empathic Darkness, which quells lights intensity whenever one feels intense negative emotion, or may make darken lit areas wherever the user goes (does not allow control of darkness); they may have Empathic Gravitation which changes gravity in ones surroundings whenever one feels certain emotions (good emotion decreases gravity, and bad emotion increases it) or the like. This ability may be accompanied by an Elemental Sense.
This ability may even entail the presence of a storm cloud that hovers above-head and reacts to the users emotions; it appears when the user feels negative emotion, rains when he feels sad, shoots lightning when he is angry, disperses when the user is happy, and the like (called an Empathic Storm Cloud).
Note: This ability causes empathic power to only affect natural elements or biotic subjects (no artificial materials like plastic, glass or artificial chemical elements, and not undead). Sometimes, Empathic Power will just affect the element that is most prevalent in ones current surroundings (sand in the desert, water in the ocean, plants or animals in the forest). This ability never produces a controlled effect (it may only be brought about by certain emotions), and so it is not the same as the ability Naturespeak or Elemental Manipulation.
Note: Empathic Gravitation, if untrained, may also induce gravitation between the user and a person with whom he has a positive empathic connection.
Empathic Resonance, also called Empathic Charm or Empathic Charisma is the ability to psychically establish an empathic link with any subject(s); parties involved can understand each other and become friends or allies almost instantly. The established empathic link is harmless (it may only last as long as needed), but it makes the user nearly incapable of making enemies (unless the ability is suppressed, or the user tries to use it on a perspicuous mind). In some cases, if foes try to strike the user, even complete strangers would come to the users defense.
Fear Sense, also called Fear Sensing or Fear/Phobia Perception is a variation of Empathy, in which the user can only perceive doubt, fear and phobia. The user can either only tell if a subject is afraid (the intensity of the fear, etc.), or they can actually intuit things that subjects are afraid of (the last, of course, being most beneficial). One with this ability can use it to easily unnerve opponents, or properly interact with subjects, because they also know how to act to prevent aversion (or perhaps even to perceive presences by sensing traces of fear), and the like. This ability may accompany Phobic Vampirism.
Musical Empathic Projection
Musical Empathic Projection is the psychic ability to project emotions based on the songs one hears. One with this ability listens to a song, and whatever emotion that song conveys, that emotion can be projected onto the subject. This ability can make masses of subjects lovesick, depressed, angry, overly-happy, or the like. Not to mention, it also psychically connects the subjects feelings to the song, so they want to hear it more, and when they can no longer hear it, their emotions temporarily short-circuit (the subjects go numb).
Telepathic Empathy is the ability to perceive emotions, but with the emotions expressed as though they were thoughts. One with this ability can read emotions of any kind, like a normal empath, but they must be expressed through verbal thought wave manifestations (the subject must think something like Im so mad! or I cant believe she did that!). The user can project emotions in the same fashion; instead of projecting emotions (like normal Empathy) the user can project thoughts which convey a certain emotion, and the like.
Telempathy, also called Tele-Empathy is the psychic ability to communicate with another subject via emotion instead of by thought. One with this ability could convey the same messages as one with the power Telepathy (including changing a subjects mind by associating a certain emotion with a certain idea or opinion, receiving/transmitting emotions to communicate, overloading foes with emotions instead of thoughts, etc.), except the message is a bit more vague. This ability may be accompanied by normal Empathy.
Twin Empathy is the emotional connection between twin siblings. One with this ability can empathically sense when their twin is in danger, how their twin is feeling, and can channel any sensations and emotions that their twin is feeling, along with all of the other faculties that go along with empathic connection (like their abilities). The user however, may also feel the pains if their sibling is hurt (and might even die if their sibling dies.
Hope this article helps you understand more on empathy abilities.