A Madness Wavelength describes the kind of Soul Wavelength in which radiates a powerful draw towards Madness. However, depending on the level in which the individual possess, a Madness Wavelength can vary in effect whether it draws others into their own Madness or achieve a specific effect.
Much of the development of a Madness Wavelength is unknown, though it is known to be considered difficult. The only known ways include
- Becoming a Kishin though only Asura succeeded in this endeavor for unknown reason (and was a Great Old One to begin with). This process is nearly impossible, as even Medusa Gorgon's efforts to make Crona a Kishin not only didn't come to fruitation from ther manipulations, Crona wasn't even showing any signs of achieving the status. Only the usage of "BREW" has enabled the capability of becoming a Kishin at a godly-like level. though the Demon Tool's granting this varies.
- Those who're incline to Madness also develop a Madness Wavelength overtime. Encounters with beings such as the Clown with their Madness Infection abilities have shown to infect individuals with a Madness Wavelength. (i.e Justin Law)
- Select individuals for unknown reasons may develop it. This includes the likes of the Great Old Ones, who's existence allowed them to have it. Even those like Arachne Gorgon can develop a high level of their own in which resembles the potency of a Great Old One.
Types of Madness WavelengthEdit
Madness Wavelengths considered at a God's Level are extremely powerful and capable of spreading across the entire Earth. In power, they're virtually absolute with little methods of countering as well as no beings (except for a select few) truly impervious to this level of a Madness Wavelength. These kind of Wavelengths give their Madness a specific, swaying effect and are born from the existence of an individual. These level of Madness Wavelength is exclusive only to the Great Old Ones. 
Kishin Level Madness Wavelengths are powerful Wavelengths in which seemingly rival that of a Great Old One's and can affect the Earth. However, as mention before, such a level is virtually impossible to develop. Only the usage of "BREW" has shown the capability of developing a Kishin (therefore, a Kishin-level Wavelength). This Madness level also gives unique, swaying effects. 
There's certain individuals who also emit a powerful Madness Wavelength, capable of being felt across the country from North America as well as having a specific swaying effect. They're either develop due to an individual simply having a powerful Wavelength or special fluids (i.e Black Blood) However, this level still falls short of the Great Old One's level and is not as absolute in power. Even certain individuals are capable of being more resistant or outright immune to.
Every living person in the world, at the very least, has a tiny amount of Madness resting within them. A Madness Wavelength of any level (Godly, Kishin, or High) can sway the insanity and magnify it, with higher levels being more effective. Due to the nature of the Great Old Ones, Madness exists in several forms (i.e. Madness of Order or Madness of Fear), with certain types being more effective over certain individuals than others, to the point where some can have either very little or very much resistance to a certain type.
- ↑ 1.0 1.1 Soul Eater Manga: Chapter 23
- ↑ Soul Eater Manga: Chapter 16
- ↑ Soul Eater Volume 5; Chapter 17, page 127
- ↑ 4.0 4.1 Soul Eater Manga: Chapter 112-113
- ↑ Chapter 53- The usage of "BREW"'s Soul Wavelength amplification didn't enable this for Death the Kid.
- ↑ Soul Eater Chapter 42
- ↑ Soul Eater Manga: Chapter 27
- ↑ 8.0 8.1 8.2 Soul Eater Manga: Chapter 23,72-73
- ↑ Soul Eater Manga: Chapter 25, Chapter 58, Chapter 113