In Guilty Crown, the void is said to be the physical manifestation of a person's "heart", but later on it is also said that it is a fragment of the soul of Mana.
What is exactly a void (besides a McGuffin)?
In Guilty Crown, the void is said to be the physical manifestation of a person's "heart", but later on it is also said that it is a fragment of the soul of Mana.
What is exactly a void (besides a McGuffin)?
From the Void Genome page in GC wiki, a Void is said to be
a person's inner psyche taking physical form.
moreover,
A Void's form and function reflects the person's fears and or complexes, in other words it's like the shape of their heart, or personality.
The definition of void wasn't given explicitly, but from what can be read in the quotes above the Void is the shape taken by the personality of a person infected with the apocalypse virus after it has been "condensed" by the power of kings.
In the page dedicated to the virus, the stages of the disease are reported:
So the Void is some kind of temporary materialization of the genome of any individual, which forms after said individual contracts the Apocalypse virus. It takes a shape which mirrors the individual's personality and doesn't really exist unless it is extracted using the power of kings.
The fact that a Void is a fragment of Mana's soul should be a consequence of the fact that she was the first one who contracted the virus.