In order to begin my theory about the Innocence , it is necessary to recall the structure of the  Pale and how it works, because the  Innocence and the Pale are one and the same - the generation of humanity's activity in the world of Elysium. 

 Pale is a mist that has no clear external forms. It is achromatic, having no colour, taste, smell or sound (questionable because of the Pale transducer, a similar device Ruby had). The  Pale represents all of humanity's time and the space in which it was, is and will be (all of each person's memories and events). 

The area of transition between the world and the Pale is called the ‘edge collapse’: a Pale mist with a cold vapour that is known to harbour a unique form of fungal microorganisms. The  Pale is difficult to describe and measure, as it is something whose fundamental property is to affect all organisms: their physical properties, and their mental ones. The further into the  Pale, the more it affects all living things. It is capable of distorting and altering non-living matter as well, down to numbers and figures.  For clarity I will describe what will happen when falling into the  Pale, many people staying in it risk going mad: first they forget everyday trifles, and later their own name, memories of who they were and what they lived. Further, when the human brain is trapped in this trap of existence, it begins to deteriorate. The spinal cord and the whole nervous system is destroyed after it. After that, the rest of the body ‘crumbles’, making it impossible to find corpses in the Pale. 

From the information in the game we know that there are already created ships with the help of which you can travel between isolas, as well as special radio stations in the Pale to send signals and coordinates of various transports (in addition to ships it can be motocarets, helicopters, etc.). Also at this point in Elysium, it is possible to travel through the Pale, but no more than six days per year (the long stay effect I described above). 

According to my theory, because of the frequent travelling between Isols, people get hit by the radiation of the  Pale on a regular basis. And even after such people find themselves far away from its effects, they are still connected to it.  This is supported by examples of characters from the game (the same trucker or Izzy from ‘Flavour’, as well as Joyce's story about Volta do Mar).

The nature of the Pale is largely unknown to the humanity of Elysium. However, according to the ending of the book - the Pale appeared because of sins: stupidity and greed of all mankind. However, as we know, any coin has two sides, and if one side has all human sins, the other side has all human virtues, and in this case it is the Innocence. 

Innocence is the physical embodiment of virtue. People who become Innocence are the major historical figures in the world, literally deities. Innocence traditionally assumes supreme rule over the world at large. The Innocence is elected by the Founder's Party; this has only happened six times in world history. 

According to the Party, everything the Innocence do and say is law.  They deserve this respect because of their influence over time and space, (whereas in the  Pale we can only look at memories and live our past, the Innocence are able to create the future). It is said that it is an honour and glory to live when one is in power. Innocence does not usually use its power through military might. It is considered unnecessary. Innocence wins because it simply cannot lose.

The legal system of the Real Belt is built from the ground up to adapt to the rule of the Innocents. The decisions of the Innocence apply equally in all countries.

There are only six Innocents in the history of the world:

Pericarnassus, the first Innocence. Little is known about her.

Franconegro, 500 years before Our Age. Considered a militaristic Innocence and the strongest among them.

Dolores Dei, 300 BC. She created many modern institutions, organised successful expeditions, even voiced criticism of the innocence system. Her beauty and inhumanity are also widely recognised. Dolores Dei is considered the greatest Innocence in the current century.

Sola, crowned in the last century. Considered the Anti-Innocence due to her unwillingness to impose her will on the world.

 Each of the six Innocence has movements of followers. For example, those who share the beliefs of Dolores Dei are called Doloreans. Their churches are places of worship for the life and ideals of Dolores. People believe that the Innocences can work miracles.

Besides the true Innocence, there have also been a few False Innocence in history - those who believed they possessed the qualities of Innocence. Sometimes they had the support of a faction within the church organisation. The most famous and important of these was Erno Pasternak. He became famous in history for his torture, despotism, and desire to conquer the world. He was eventually destroyed by Stepan the Despicable of Cedra, for all the nobility of his deed he never became an Innocence.  

Why? 

They just don't get elected on the politicians' side (as a tool). Because of this, there are no Innocents in ‘53: the Coalition is simply not profitable, because altruistic motives are less reliable than money or the Coalition itself. It follows that an ordinary person can't become  an Innocence through their deeds alone - you have to get recognition from the people or the Party to do so. 

There are hints in the game about the non-human nature of the Innocences. For example, when Harry is talking to the Encyclopaedia, the reason for Dolores' murder is described.

There have also been theories that Harry is the new Innocence, just because of the case of amnesia and the ability to talk to his emotions, organs, and the city itself, but unfortunately this is not the case. The Innocence can't forget who they are, unlike Harry. They were also notable for some larger actions: discovering other isolas, uniting nations, etc.

These abilities are more akin to the Pales, and perhaps the voices in his head are just thoughts of his dead alter ego in the past, which makes sense. The female voice, which is Dora's voice, talks about everything that will happen in the future, possibly to guide Harry. (We won't wait for the second part of the game, though, so maybe not to guide...)

This led me to a hypothesis, the idea being that people who have been exposed to the  Pale can control it. When playing the game, this is confirmed by the periodic tests that Harry must pass. He can pass them by improving one or more parts of his personality.  (See the picture below). Another person who has encountered the Pale is a trucker whose ability is to move into the bodies of people who have lived in the past, present or will live in the future.

What if there is a person who can control the bodies of people who are possessed by the Pale?  

If there was Sola, who said to rely on ourselves and not on the Innocence, then I think there are people in the world of Elysium who can master the Pale enough to control not only certain memories of people, but also their bodies. Maybe there is such a ‘sanitiser’ in the world of Elysium, who can introduce souls and lost memories into the bodies of people who have lost them.