The secret to turning defeat into victory originated from a natural phenomenon, the impending rain.
The Demon Clan's army was so eager to attack because the rain was about to start. Yichuan Long hesitated for the same reason.
The Demon Clan's army had not yet developed cartridge technology like Earth, which made their firearms extremely dependent on the weather. Once they encountered such damp, rainy conditions, the efficiency of the Demon Clan's firearms would drastically decrease.
Yichuan Long had clearly realized this, which is why he chose to engage the Demon Clan at such a moment.
On the side of the Demon Clan, Yunji was also aware of the weather condition. However, overconfident, she believed that the Demon Clan could crush the Yichuan Clan's Nine Thousand Battalion before the heavy rain.