Noise are a race of beings, summoned physical forms from a Soul bound to a Pin, incarnated between the Underground and Realground planes of Shibuya. Because they straddle the border between the two planes, they are able to exact an influence in both, being physically present in the Underground, while capable of influencing people's thought in the Realground, typically resulting in negative emotions on the victim's behalf.
Noise take on the form of an animal or mythical creature, colored in a wide variety of palettes. It is worth mentioning that the Noise at least has a part of its body lined with or replaced with tattoo-like patterns.
In battle, each Noise typically has two incarnations, one on each screen. The two incarnations share HP, meaning that attacking the same creature in both screens simultaneously is a quick way to defeat single enemies.
However, some enemies have only a single incarnation on a single screen. Examples are:
- Sprog Noise (which exist on the bottom screen and are automatically defeated when the frog they appear with is defeated)
- Shrew Noise (appears from different holes, 4 on the bottom screen and 2 on the top they can also spin like a drill and create new holes on either screen)
- Reapers (who can exist on one screen at a time, switch screens, appear on one screen with a shadow on the other, or be so massive they take up both screens)
If there is more than one Noise of the same type on each screen, the player can sometimes find out which Noise on the upper screen corresponds to which Noise on the bottom screen -- for example by using Joshua locking ability. This proves useful for targeting one Noise at a time to eliminate it faster.
When scanning, the six different types of Noise symbols can be distinguished by their color:
- Chump Noise - Red
- Pig Noise - Green
- Taboo Noise - Black
- Negative Noise - Yellow
- Boss Noise - Blue
- Dissonance Noise (Exclusive to A New Day) - Purple
Noise symbols float about a small radius awaiting a tap from the stylus to initiate combat. Taboo Noise are the exception to this rule as they will float towards Neku and force him into an encounter. If a Noise has already reached Neku, one can scoop up the Taboo Noise by dragging another Noise, and simply hold them there until the timer for battle-preparation expires.
In addition to their color, Noise symbols come in various shapes that vaguely resemble a Noise's skull, each shape typically holding a certain Noise combination depending on the location and day.
Noise possessing people drag down the emotions of the possessed. These Noise are also drawn to hotspots of negative emotions, creating a feedback loop of increasingly negative emotions. The ultimate result of this is unknown.
Certain powerful Reapers, those of Game Master rank or above, are able to transform into alternate Noise forms more suited for battle. Angels can take on Noise form in an identical manner.
Taboo Noise are especially powerful Noise. They cannot be born naturally and must be refined using techniques forbidden from Reaper knowledge; their creation is a capital offense according to Reaper rules. Whereas normal Noise cannot attack Reapers or Players with a Pact, Taboo Noise freely attack both. It is impossible to run from them, and they take much less damage from attacks than other Noise unless the attacker has the Light Puck.
Information from the Secret Reports
All Noise are composed of Soul, just as all consciousness is in the Underground, and are born when Soul is bounded to the code of a Reapers' pin or the negative emotions of people. However, these monsters do not have any free will of their own and exist only to multiply and consume the Soul of people in the Realground by possessing them.
Even after they are erased, the Soul the Noise consume is destroyed permanently, but the freed human experiences a rush of euphoria...They exist on a special plane that is both on and in between the RG and the UG. Though the RG and the UG exist in the same space, the Noise plane is split into two separate spaces. Every Noise exists in both spaces at the same time, and though they share the same life force they can move around individually.
- Within the context of The World Ends With You's popular culture and modern day fantasy spiritual settings, Noise are similar to the concepts of demons, and specifically that of "inner demons". Going into the arts, Negative Noise may also likely represent a corporeal manifestation of spiritual imbalance and mental disorder, including mental illnesses, emotional disturbance, and addiction. Within popular thought and human history, it has been documented that popular and historically significant figures, including those within the arts, are also said to be eccentric or exceptionally different in their ways of thinking, including how such manners of thought and soul lean not just to the admirable and remarkable but also to harmful and abnormal. Such episodes of negative displays of behavior in this sense may be attributed to how Noise steal and feed off of the imagination of these individuals, which causes them to act irrationally and disturbingly unlike themselves.
- Within the context of music, Noise's music theming may also likely refer to how music is created through a need to express one's inner selves, and this may include how such imaginative interference caused by Negative Noise demands one to rely on other creative faculties that are untouched rather than the kind one's parasitic noise drains. In real life, it is not unheard of the lifestyles of musicians sometimes dabbling in drugs and with personal lives marked with unhealed wounds from earlier points of their lives; examples may be found in singers like The Red Hot Chili Peppers lead singer Anthony Kiedis and Guns N' Roses singer Axl Rose, and some notable late musicians who have long suffered from this include Nirvana lead singer and founder Kurt Cobain, Amy Winehouse, and Linkin Park lead singer Chester Bennington.
- In The Animation, Negative Noise and Chump Noise have their purposes merged but retain the color scheme of Chump Noise. They are only show possessing people in the UG.