Makou has always been a part of human existance, but in a relatively short period of time it has become all but indispensible to the human race.
When makou is sufficiently far removed from the lifestream that it becomes stagnant, it will crystallize. This results in the huge ice-crystal formations found in the crater north of Knowlespole. These crystals can be harvested for their energetic properties.
The access most people have to makou is via materia, small smooth crystals with various energetic properties tied to their colors. In the past, materia has been found mostly by scavenging around natural pools of makou, where it resulted from crystalline formations being worn smooth and round by the active lifestream. For the last thirty years, Shinra has been producing materia from raw harvested makou crystals, tumbling the rough stones into perfect spheres suitable to power weaponry and be issued to the military. These materia are slightly weaker than the natural materia, but have more practical applications.
Makou itself is phosphorescent in its natural state, giving off some energy as light much as other energy sources such as the sun do. It is also, despite being in a liquid state, very unstable when processed or stored. The makou is showered on the SOLDIERs and absorbed through the skin. Instead of killing cells as radiation does, however, a reasonable quantity of makou and its derivatives in the body produce increased cell growth in muscles. The effect also invades other bodily fluids and its heavy presence in the “salty” tear ducts leads to the SOLDIER program’s most obvious outward sign, the glowing eyes.
The energetic components of makou are adapted into the brain and nervous system of the SOLDIER. This results in increased speed and reaction time, enhanced senses, and superior brain capacity. In short, makou energy in the neural pathways creates a far more efficient human machine.
The introduction of too much makou into the human body, however, can have devastating effects. The problem lies not in the body but in the mind. With high levels of makou exposure come far greater levels of mental activity. Both incoming and outgoing nervous reactions are exponentially increased until there is too much sensory input for the mind to process and/or too many movement signals for the body to process. This can result in a coma or wild seizures, sometimes both, depending on which set of signals is overloaded first. This is known as “Makou Poisoning” and recovery is almost unheard of. Occasionally a very mild case, removed from all makou exposure and watched carefully, can process the makou in the system and bring it back into balance. These few survivors described hearing voices speak to them, calling them. Superstition calls this the voice of the Planet. Some forms of schizophrenia can be triggered by chemical imbalances in the brain. I will leave it to the reader to speculate further. The vast majority of cases of makou poisoning result in a slow deterioration of the body followed by death.
While some experience with makou has always been common on the Planet, it seems clear that the importance of makou in the life of the average human has increased dramatically with the developments of the Shinra company and its derivative corporations.