The most famous Thunder Fire Pill is used by Third Tribulation Realm cultivators during the Heavenly Tribulation of Thunder and Fire. It can increase their affinity with thunder and fire, greatly enhancing their resistance to the tribulation, thus increasing the success rate of crossing the tribulation.
A furnace can produce at most three pills, and it takes 2,800 years to form them.
If you don't want to wait, you can use other methods of alchemy, preparing three sets of materials in advance.
If your luck isn't too bad and the people you find are reliable, there's a chance you can successfully make one batch.
Unfortunately, even in the Divine Dynasty, without absolute necessity, it's impossible to waste rare top-tier materials in such a way.
Two thousand years is not much, just wait patiently to be prepared for the future.
What they use now are those that started being refined over two thousand years ago.
