And the speed at which cultivators improve their strength is excessively slow. It's not like participating in high-intensity battles can quickly enhance one's power; that's a privilege reserved for the protagonist. Normal cultivators really won't see their strength increase if they just fight without cultivating, but they're sure to lose their lives quickly.
Cultivation itself is a process of gradual improvement over time; there are not so many breakthroughs during battle or sudden realizations, more often ends in death on the battlefield.
"After fighting for so long, what's depleted is not just the population but the number of cultivators as combat personnel."
Although Gu Shanhai feels that the losses on the Demon Race's side might be even more severe, if the fighting continues, they might win, but it's likely to be a Pyrrhic victory.
