Spontaneous Human Combustion

is a worldwide phenomenon that appeared shortly after The Great Disater that causes humans to instantaneously burst into flames. In some cases, humans can adapt to the flames and awaken the ability to manipulate flames or ignite themselves or objects. The origins and selectivity of the phenomenon are unknown. The Special Fire Force have made it their mission to unravel the secrets behind it.

Overview
Humans effected by SHC are transformed into creatures known as Infernals as a result. While in this state, the victim is able to create fire at will and is effectivlly immortal unless their core is destoryed. The change also leaves them in constant pain, which forces the majorty of cases to lose their self-awareness and sanity. Turning them into rampaging creatures attacking indiscriminately or driven by simplistic desires from their human selves unless stopped by force. However, some victims are able to remain in control of themsleves to a certain degree or, in cases with a notably stong will, remain in complete control of themsleves and use their new body freely. As if to natrually combat this condition, humans have also begun to adapt to SHC. People born with the ability to manipulate flames are known as Second Generation of pyrokinetics while those with the ability to create and control their own fire are known as the Third Generation. As both groups are partly resistant to being hurt by fire, people in Tokyo often end up becoming Fire Soliders in the Special Fire Force; though not always.

Causes
One of the key mysteries about Spontaneous Combustion is what caused to appear and how it spreads. While in some cases it is totally random and sudden, it is also possible to deliberately trigger it uses a certain type of insect. Once stung, the victim either transforms into an Infernal or awakens their pyrokinetic abilities.