Appendix: Power Modifiers Game Mechanics Details
The following power modifiers are either common or unique to the Marvel Universe. Others, such as Chi, Mechanical, and Spirit, usually only appear in isolated cases.
Biological (-10%): These abilities are part of the character's physiology, but may be negated through the application of drugs geared specifically for such purpose (-5%). Active abilities always require an additional 1 FP to use (-5%), but see Passive Biological, below.
Chemical (-10%): These abilities are dependent upon some form of chemical/alchemical potion being applied to the body on a regular basis, whether through ingestion, inhalation, or injection. This potion is the equivalent of Maintenance (One Person; Weekly) (-5%); the potion takes at least an hour to create. In addition, the effects of the potion can be counteracted through other pharmaceutical means, same as with the Passive Biological power modifier, below (-5%).
Demonic (-10%): The infernal counterpart to the Divine power modifier from Powers. These abilities are granted by supernatural entities that are at best uncaring or more often actively malevolent (a "demon"). The entity requires the character follow a -10 point self-imposed disadvantage of the demon's choosing, which may not be one of the 'heroic' disadvantages. Should the character violate the demon's code, the demon will remove the ability. Demons are notorious for removing the ability immediately upon violation, even (especially!) in life-threatening situations (-0%), and usually requires only a minor quest or minor harm to restore (-0%).
Divine (-10%): The more beneficial counterpart to the Demonic power modifier. These abilities are granted by supernatural entities that are at generally benevolent, quite possibly one worshipped as a god at some point. The entity requires the character follow a -10 point self-imposed disadvantage of the deity's choosing, which is usually one of the 'heroic' disadvantages (-10%). Should the character violate the deity's code of conduct, the deity will remove the ability. The deity in question will likely remove the ability immediately upon violation, except in immediately life-threatening situations (+5%), and usually requires a major quest or act of penance to restore (-5%).
Electronic (-30%): The most common version of Technological in the Marvel Universe. The power's abilities require weekly maintenance, at 1 hour per ability (-5%). In addition, they can be detected by X-ray scans and other forms of medical imaging, and may also generate radio static or an odor of ozone (-5%). Finally, they’re vulnerable to electrical disruption as defined for the disadvantage Electrical (p. B134; -20%). This last portion is identical to taking the Temporary Disadvantage: Electrical limitation; do not take the latter with this power modifier.
Elemental (-10%): This power lets a character manipulate an "element" – one kind of natural matter or energy, or its absence. Common examples in the Marvel Universe are Air, Cold/Ice, Darkforce, Earth, Electricity, Heat/Fire, Light, Radiation, Sound/Vibration, and Water. These powers have either a mundane countermeasure (-10%) or an insulator (often but not always an opposing element) that can interfere with the elemental energy (-10%), but rarely both. Unlike other power modifiers, Elemental may stack with either Super, Psionic, or Mutant.
Magical (-10%): The character's abilities are dependent on the world's ambient mana to operate. The bulk of the world appears to be a normal-mana region, while certain areas of the world are low- or high-mana areas. Modern technology cannot detect these energies, so there are no technological countermeasures. However, the ambient energies can be blocked through paranormal means (-5%), and the abilities can be negated through certain Anti-Magic abilities (-5%).
Mutant (-10%): The character is a mutant whose abilities can be negated through Anti-Mutant abilities such as Neutralize and Static (-5%) or through technological means (-5%). This is a subset of the Super power modifier, so any Anti-Super abilities will also negate the mutant powers, but the reverse is not necessarily true.
Mutant Biology (-0%): The character is a mutant, and can be detected as such. However, the abilities with this power modifier are physical adaptations which cannot be removed except through surgery (usually amputation of limbs), and are nearly indistinguishable from "wild" abilities, but do receive the skill bonus from Power Talents. Because of this, there is no value to the modifier. Technically, this would be considered a subset of Mutant, above.
Mutant Psionic (-10%): The character is a mutant and can be detected as such. The character's powers are psionic in nature, usually Telepathic, ESP, or Psychokinetic, and can be negated by both Anti-Mutant and Antipsi abilities (-5%), or through technological means (-5%). This is a subset of both the Mutant and Psionic power modifiers, which are themselves subsets of the Super power modifier, so any Anti-Super abilities will also negate the mutant abilities, but the reverse is not true.
Nanotech (-15%): The Power's abilities require weekly maintenance, at 1 hour per week per ability (-5%). In addition, they can be countered by nanotech designed by adversaries (-5%). The operation of nanotech is biologically stressful: Pay an extra 1 FP whenever you use an active ability (-5%) in much the same manner as for the Biological modifier.
Passive Biological (-5%): Like Biological above, these abilities are part of the character's physiology, but may be negated through the application of drugs geared specifically for such purpose (-5%). As these abilities are passive in nature, no FP expenditure is necessary.
Passive Nanotech (-10%): The power's abilities require weekly maintenance, at 1 hour per ability (-5%). In addition, they can be countered by nanotech designed by adversaries (-5%). These abilities are passive in nature; no FP expenditure is necessary, unlike with Nanotech.
Power Cosmic (+10%, +20%, +30%, +40%, or +50%): These abilities stem from cosmic sources, and are not easily counteracted by anti-powers, pharmaceuticals, or superscience technology designed to counteract other powers. Only other Power Cosmic powers of a higher tier can counteract them. This is otherwise identical to the Cosmic power modifier in GURPS Powers. This is a leveled modifier, with the more powerful levels able to interfere with and/or override lower levels. In practice, only the Living Tribunal possesses the +50% version, and corporeal cosmic entities such as the Watcher and those of the same power level have the +10% level.
Psionic (-10%): The character's abilities are psionic in nature, usually falling under such classifications as Telepathic, ESP, or Psychokinetic. As such, they are affected by Antipsi abilities (-5%) as well as technological means (for example: psionic dampers) (-5%). This is a subset of the Super power modifier, so any Anti-Super abilities will also negate the psionic abilities, but the reverse is not true.
Super (-10%): This is a catch-all power modifier for those powers whose abilities are not biological, psionic, magical, or mutant in nature. Mutant and Psionic are both subsets of this. These abilities can be negated through various Anti-Super powers (-5%) and through technological means (-5%).
The Venn diagram to the right shows the correlation between the Super, Mutant, Psionic, and Mutant Psionic power modifiers. The gray are represents those powers that fall under the Super header. The cyan area represents those that fall under the Mutant modifier, being considered "mutants" in the Marvel Universe. The yellow area represents the powers that full under the Psionic power modifier. The green area which overlaps both the Mutant and Psionic areas represents those mutants whose powers are also psionic in nature.
In any given campaign, only one, and possibly two, of these four should be prevalent. In an X-Men campaign, Mutant will be prevalent, with a few Mutant Psionic and Mutant Biological powers thrown in; in an Avengers or Fantastic Four campaign, Super will be the most common, with a few Psionic powers available; and in a supernatural (Doctor Strange or Hellstorm) campaign, Magical and Demonic are the most likely power sources for PCs. The overall frequencies of countermeasures for each of these four categories are about equal, hence the lack of difference in price. Of course, in truly crapsack campaigns (such as the Secret Wars story arcs), all bets are off. In such a campaign, it is acceptable to boost both Psionic and Mutant by -5% (to a total of -15%) and Mutant Psionic by -10% (to a total of -20%) to reflect the vulnerability to a wider range of available countermeasures.