Flame.
The beginning of the story starts in ancient times, a raging fire swept down by lightning in the storm, devouring the forest; it is the spark ignited from the clash of stones in the hands of bipedal apes in dark caves.
Countless years have passed, and sentient beings have long been accustomed to this fiery substance.
Dispersing darkness, bringing warmth, forging tools...
Even an illiterate countrywoman who has never stepped out of the fields or valleys understands how to light wood and use its scorching heat to cook meals.
But to this day, it has never been tamed.
Raging through urban areas, burning forests... even the faintest flame on a candlestick can lead to a catastrophic disaster devouring countless lives.
Xia Nan, of course, understands its power.
From his past life, the profound lessons inherited from humanity's history over millions of years have deeply instilled in him the potentially extreme adverse effects of this substance.
