Magic. The great equalizer, according to the CS. More powerful and more surgical than a thermonuclear bomb, magic is the ultimate equalizer on Rifts Earth. While many horrible beasts walk the land, many magicians, good or evil, can use their powers to subdue, banish, or annihilate them. The unfortunate drawback of magic is that it is derived from one of three things: Ley Lines (PPE), Inner Strength (ISP), or the user's life force (Chi). Regular mages can gain tremendous boosts from nearby ley lines, while Psychics can gain only a small one.
Sometimes, fighters are just not enough. Your mages might be underpowered because you are too far from a ley line, or maybe there's a Nega-Psychic around. This is where the Psychic has his chance to really make an impact. Psychics are mages, but, instead of drawing most of their power from ley lines, they draw their power from their Inner Strength. Psychics are often a key component in a party, having special abilities that vary from psychic to psychic, depending on class and abilities. Psychics are an R.C.C, which means that they get different bonuses than regular O.C.C.s. For example, a Zapper has the intrinsic abilities Telekinesis and Electrokenesis. However, because of his class, his innate abilities are much more powerful than if, say, a Mind Melter or a Burster had the same abilities, even if they were higher level than him. ISP is consumed with each ability used, unless stated otherwise. The downside of ISP is that, if you go into the negatives, you're dead. Now, some GMs may allow your sacrifice to make a super-ability that wreaks havoc on the enemy, but this is entirely up to them, and is NOT a rule of the game.
While generally reserved for superhero games, such as Heroes Unlimited, it is also possible that characters with superpowers exist in Rifts. In fact, Conversion Book 2 contains rules for using Heroes Unlimited superpowers in Rifts, while Skraypers and other Phase World sourcebooks contain races and OCCs with superpowers.
Other skills include Chi and Martial Arts skills. Some of these skills vary based on race (e.g: the Teng-jutsu abilities are much more potent if the player race is Tengu). Chi is similar to ISP in the sense that, if you run out, you're dead. Chi is essentially your life force. However, it is pretty difficult to actually find how to determine what your Chi is. We actually have no information on where you can find this, but we'd suggest looking in Rifts: Japan.