In the world of Ground Zero, some degree of psionic capability is surprisingly common. Centuries of tinkering with the human genome, as well as random mutation and the generally increased level of paranormal activity on the planet has seen to that.
Many different mutations can unlock psionic powers which allow the character to perform extraordinary feats, as can some talents. The unlocked potential varies greatly from character to character. Some barely understand the true nature of their latent mental powers, while others learn to master and expand their gifts.
(I've recently changed these rules so that advanced psionics closely resemble the Expanded Psionics Handbook system from D&D. One noticable difference from the standard rules is that I call them 'Inner Strength Points' (ISP) instead of 'Power Points'.)
Sometimes mutations develop in the brain rather than the body. Psionic powers gained in this manner are considered innate psionics (as opposed to advanced psionics - explained below - which draw on a character's inner strength).
The following mutant perks are psionic in nature: Call to Mind, Cloud Mind, Conceal Thoughts, Danger, Sense, Detect Hostility, Detect Psionics, Dispel Psionics, Empathy, Empty Mind, Missive, Object Read, and Thought Shield.
Many other psionic powers are considered uncommon perks: Body Adjustment, Burst, Charm Person, Clairvoyant Sense, Concealing Amorpha, Concussion Blast, Dimension Swap, Ectoplasmic Cocoon, Empathic Transfer, Entangling Ectoplasm, False Sensory Input, Far Hand, Fate Link, Precognition, Read Thoughts, Telekinesis, and Vigour.
Note that there are also many mental mutations that are not psionic (Independent Cerebral Control, for example). Psionic mutations are denoted by the superscript Psi in the mutant perk tables.
Innate psionic powers work just like any other mutation. The descriptions for these innate powers (see the Mutation Descriptions page) omit details which apply only to advanced psionics; advanced psionic practitioners may be able to manifest these powers differently (see below).
While those with innate psionics tap the power of the mind, advanced practitioners embrace the total energy of consciousness directly, utilizing this inner reservoir of power to effect change in the real world. Characters with advanced psionics have a limited pool of 'Inner Strength Points' (ISP) which are used to activate their psionic powers. As the character gains levels in a psionic class, he gets additional psionic powers and more ISP.
Your ISP reserve is equal to your base ISP gained from your class, plus your Charisma modifier, and any additional bonus ISP from sources such as your genotype and talents. Inner Strength Points are regained through contemplation and meditation; the character must rest for 8 hours then spend 15 minutes meditating to recharge his mind and ISP.
Psionic powers are listed and described on the following pages (simplified descriptions for innate powers are included separately in the Mutation Descriptions page):
Characters who are advanced psionic practitioners and also possesses innate powers can learn to activate their innate powers using ISP. When an advanced practitioner gains access to powers of a given grade (minor, medium, or major) as a class ability, he also adds any innate powers of the same grade to his 'powers known' list, as long as he also meets the Charisma prerequisite (Cha 12+ for minor powers, Cha 14+ for medium powers, and Cha 16+ for major powers). The character can still use his innate powers in the regular fashion, but gains the flexibility of manifesting them as advanced powers.
Psionic powers gained in this manner work just like any other advanced power. They are activated at the character's usual manifester level - even if they are manifested at a different level when used as innate powers - and can be augmented (if applicable).
The new skill 'Knowledge (Psionic Lore)' covers psionic powers, psionic traditions, and psionic races. You can use this skill to identify psionic powers as they are manifested or powers already in place. You can also identify psionic monsters and their special powers or vulnerabilities.
Knowedge (Psionic Lore) is a class skill for the thinker class.
The following thinker talents grant psionics to a character or improve his psionic capacity. Only those with a strong psyche (high Charisma) can learn psionic talents. 'Wild Talent' unlocks a character's psionic ability, while the 'Inner Strength' and 'Psionic Knowledge' talents increase his power:
Psionic talents are considered class talents for the thinker class. Note that 'Wild Talent' allows a non-mutant to gain psionic powers.
To gain true psionic power, you will need to take levels in a psionic advanced class:
Non-mutants will need to select 'Wild Talent' (described above) to gain access to these advanced classes.