This guide is designed to help new players unfamiliar with the A Certain Scientific Railgun/A Certain Magical Index setting and lore to create appropriate powers for characters. Though Railgun/Index's setting features what are nominally “psychic” powers, it can be easy to create powers that fall more within the realm of “magic” than “ESP”, or make a power that's unintentionally too powerful.
This guide assumes that you have a basic understanding of the nature of psychic powers in Railgun/Index.
Short version: Read this section if you're in a bit of a hurry, and don't have time for an in-depth explanation.
To explain things as simply as possible, here are 5 quick rules for making a power for Academy City ITP:
Characters don't need to have powers to be interesting. The main villain of the current plot arc has none, for example.
In general, ESP powers tend to exploit a single scientific phenomenon. Examples include; control over velocity vectors of particles (high level telekinesis; Accelerator), control over electrons (electrokinesis; Misaka Mikoto and clones thereof), control over the thermodynamic properties of matter (keeping an object at a constant temperature; Kazari Uiharu), and application of equal and opposite force on a moving object (Hitsushi Tsutomu). Don't forget to check the powers list to see if another existing character already has dibs on a power that you're thinking about!
Don't be afraid to discuss the power with other players. Also, it is important that you be patient when other players point out flaws and make criticisms of your proposed power; even if they come of as being rude, it will help no one if you retort harshly. First drafts of powers are unlikely to come away unchanged, and it is highly unlikely that initial proposals for powers will end up being 100% the way it was by the time it's implemented on to an active character. As long as you're reasonable about you want, though, it's quite certain that the core premise of your proposed power will remain intact.
Think about in detail what sort of consequences will ensue when your character uses a power. For example, if your character can create portals, then what happens when you create a portal within a solid object? If your character has the ability to telekinetically move around nitrogen, he should also be able to remove nitrogen from chemical compounds and organic matter (like human bodies); if the latter ability isn't what you're going for, you need to be able to explain why your character can move around nitrogen when it's inside a compound but not outside.
Think very, very carefully before you make a Level 5 character or a Gemstone1 character. Level 5 characters are incredibly rare in the world; in the source material, there are only 7 of them in existence out of a world wide population of roughly 6 billion people, and they are some of the single most powerful people alive. Such a character will have incredible ramifications on the story and the setting. If you're going to make a Level 5 character, you must be prepared to shoulder a very large amount of responsibility; entire plot arcs may revolve around your character. All of this also apply to Gemstone characters, and it is especially important to understand that making a Gemstone merely for the purpose of making a unique and exotic power is frowned upon. Ask resident Railgun/Index expert Kasanip for more information as to why Gemstones are not to be made on whim. At the time of the writing of this guide, no more Level 5 or Gemstone characters are allowed.
Long version: Read this if you want a much more in-depth look into power creation in Academy City ITP.
First, let's reiterate the 5 rules outlined in the short version.
Remember that you don't have to make a high-powered character to play an interesting character. This applies to any piece of fiction or Freeform RPG game where people have (what are to us) superhuman powers; great powers are NOT a necessity for a great character. If you really want to have a character with psychic powers, by all means go ahead, but don't feel that you must create a character with powers to create a significant character. Some significant characters in the source material are without supernatural powers (magic or psychic); some plot-critical characters in Academy City ITP are likewise without supernatural powers. You're encouraged to create a character, a person, not a collection of abilities with a personality tacked on.
Psychic powers in source material tend to rely on exploiting a small number of physical, chemical, or biological phenomena to some degree, or otherwise interact with AIM fields. These can range from being relatively broad (telekinesis on particles of matter, such as Accelerator's powers) to relatively specific (Saiai's telekinetic control over nitrogen atoms and only nitrogen atoms). Meanwhile, the only verified psychic power that directly has to do with AIM fields is Rikou's ability to track the location of specific AIM fields (and with the addition of certain power-boosting drugs, emulate them). There are, of course, exceptions to this rule, usually with powers that are traditionally accepted as being psychic powers, such as telepathy, remote sensing, and teleportation; nonetheless, you should try to at least take the time to explain these abilities using a more scientific than magical style; remote sensing, for example, could be rendered as the ability to “create stimulus receptors that the user can directly transfer to his brain”, while telepathy could be excused as “the ability to detect brain wave patterns and translate them directly into thoughts”.
As this is a Freeform Roleplaying Game, it is critical that you become comfortable with discussing various issues with other players, and it is especially critical that you become able to do so while keeping your temper in check. Academy City ITP has not had any especially threatening conflicts amongst its players, but tempers can easily lead to tension, which in turn can easily make the game not fun. And what use is a game that isn't fun? It's a waste of time. Therefore, you are strongly, strongly encouraged to not take things personally when someone criticizes a power that you made, or points out flaws in your character. Do not lash out against critics, no matter how harsh they may be; if they step out of line, rest assured that we will deal with them accordingly.
Critical to inventing a power is considering what sort of unintended side effects it will have on the environment, on other people, on the setting, and on the plot. This is, admittedly, somewhat difficult to do, especially if you're not particularly scientifically inclined, but nonetheless it is highly worth thinking about. It's easier to run across unforeseen consequences of powers if they're relatively broad; if you have control over vector velocities, then with sufficient control and power you could easily create a nuclear fusion reaction (which actually happens in source material). If you can teleport yourself and objects inside other objects, then you must consider what happens when you teleport a large pane of glass into someone's torso, or a building's structural support. If you create a simulacrum of a sensory organ, then you must consider what happens if too much stimulus is delivered to the sensor (loud noises, bright lights, etc.). Related to this is the fact that some powers are “subsets” of other powers; in other words, some psychic powers can easily be replicated by other psychic powers. Telekinesis over particles means that you can do all sorts of things, from nuclear fusion, to control over radiation, manipulation of the 4 major forces (strong nuclear, weak nuclear, electromagnetic, gravity), to levitation, to electro/hydro/pyrokinesis, and each of the things listed could easily be a power of their own. Thus, if you're going for a power with relatively broad, sweeping abilities, remember that your character should be able to use these subset powers. If you don't want your character to be able to use those subset powers, you must provide some kind of explanation for as to why. Parameters of a power are also important, but we'll discuss that later.
In general…you should probably not think about making a Level 5 or a Gemstone character, especially the latter. Even the best roleplayers will be turned away from these roles if it is determined that the story is too saturated with high-level characters. This is doubly true in the case of Gemstones; because they're so unique, rare, and powerful a phenomenon (possibly greater than Level 5s), to play a Gemstone character is to play a character who will be very, very important to the plot. Playing a Level 5 or a Gemstone means that you'll be playing someone who's almost literally one of a kind; out of the billions and billions of humans living on Earth, only 7 of them are Level 5s, and perhaps fewer still are Gemstones. You will potentially be playing someone more important than the political heads of most countries. This is a great responsibility, one that we won't give out lightly. Don't create a level 5 just because you want to toy around with god-like powers; don't create a Gemstone just because you want more flexibility on your character's powers. Talk to Kasanip for further explanation as to why we're highly unwilling to let people play Gemstones.
So, with that aside, let's talk about some more specific issues on Railgun/Index style ESP powers.
Distinguishing between Magic and ESP
This is something that trips up a lot of newer players and players unfamiliar with source material. As magic is strictly banned in Academy City ITP, it's quite important that you make powers for characters that fall within the realm of ESP and not wizardry. To be fair, the divide between magic and ESP in Railgun/Index can be somewhat blurry at times, or even arbitrary, soo help clear things up, here are some basic guidelines.
The easiest rule to follow is this; if the power you're thinking of would be considered to be a psychic power in most other works of fiction, then it'll almost always be a psychic power in Academy City ITP, as long as you try to justify it somehow. Levitation? Not a problem; it could easily be telekinesis over your own body and only your own body. Teleportation? Call it a space-time manipulation ability, or something.
Another easy to follow rule is the matter of artificial intelligence, not computer AI but the act of giving an inanimate object or objects the ability to think on their own, being able to receive verbal or thought commands, etc. Even animal-intelligence is dubious. Thus, things like independently-thinking golems or skeletons do not really fit, though with creativity and skill one could give the illusion of such powers (such as fine telekinetic control). In any case, a psychic creating synthetic intelligence is, at the very very least, well within the territory of Level 5 or Gemstone powers, and even then it is somewhat unlikely that such a thing will be allowed. In short, you should avoid making powers that create within something the ability to independently think.
Complex abstract ideas tend to fall within the realm of magic. The creation of fire is fine; it can be easily explained as the facilitation of spontaneous combustion, the lowering of flash points in objects around the user, and so forth. But powers labeled as “the ability to induce death” or “control dolls” and such are more dubious. What exactly do you mean by “death”? Do you mean clinical death? Brain death? If it's brain death, then that implies that you have some sort of control over an important substance in the brain (neurological chemicals, water, iron, oxygen, etc.), and therefore your character must be able to control those substances when they're outside of a brain. Why can you control only dolls, and nothing else? Telekinetic control over specific elements or molecules is fine, but dolls tend to be made out of a large variety of molecules and elements, and if your power is simply telekinesis in general, then your power is not just “control over dolls”, it's “control over all mater”. Of course, this is not entirely a hard and fast rule; perhaps your character has the ability to manipulate water, including the water inside human bodies, and you elect to halt blood circulation inside someone's brain, inducing a stroke; perhaps your character had a traumatic incident that created a mental block on him that prevents him from exerting his telekinetic powers over things that his brain doesn't recognize as dolls. However, we would appreciate it if you avoid using the "trauma" explanation as a convenient way to convert magic in to psychic powers; some things, no matter how well they are justified, will come off as being more magical than psychic, and once again magic and magic-like phenomena are prohibited.
Plenty of powers can easily be classified as either magic or ESP; in these cases, simply explain the power in scientific terms and you're done. It's not a fireball—you're just using your control over oxygen and hydrogen molecules to facilitate combustion. It's not a lightning bolt spell—you're simply manipulating electrons to zap a target. You're not summoning a giant sword—you're using your control over iron to make one out of surrounding materials. But again, please take care not to tread too deep into the realm of magic and try to spin it off as a psychic power; the ability to summon angels will raise a few eyebrows regardless of how you try and explain it.
As you should know, there are 6 levels of psychic powers in Railgun/Index, 0 through 5. There are some important things to remember about this:
Level 0 does NOT necessarily mean that one does not have a psychic power. Motoharu's power, which is confirmed as being a psychic power, simply lets him regenerate from otherwise mortal wounds, which is arguably more powerful than many Level 1 or 2 powers, yet it is considered to be Level 0. Remember that Level 0 means that either the person has no powers, or has a power that is too difficult to easily measure and categorize into Levels.
An adult with firearms training and a decent gun is considered to be the equal of a Level 3 ESPer in combat. This is a useful tool for gauging the strength of your power at level 3; how dangerous and powerful is your character's ability compared to an adult with a gun? Will your character be able to defeat such a person one on one? Granted, this tool is best used to determine combat abilities and therefore is more difficult to apply to characters with non-combat powers (such as remote sensing or healing), but it's a good place to start nonetheless.
Everyone, except in the case of Gemstones, must undergo some kind of training to fully use their psychic powers; except in extreme circumstances, it is almost assured that your character, if he or she has not been a student at Academy City for some time, will start off being of a very low level, probably 0. Of course, you can easily have your character work his way up to a specific level—very quickly, if you wish it—but also remember that most people will hit a wall somewhere, despite their best efforts and the finest training regimen that Academy City can offer. Not everyone gets to be Level 5, unfortunately.