These were not the most terrifying things.
Some barbarians could master the method of entering Tier 2 after being stimulated mentally, and their strength would experience explosive growth.
However, the barbarian's overall lifespan would also be greatly reduced after entering Tier 2.
After a long period of research, the Empire's scholars believed that the barbarian's Tier 2 state was a combat technique that consumed one's life potential.
They were using their lives in exchange for a short period of strengthening.
It was undeniable that the barbarians posed a great threat to the Empire.
Under the pressure of the barbarians, the Empire integrated and unified the martial arts cultivation system, and this was passed down within the Empire's military.
After that, martial arts techniques were gradually promoted and spread widely in the Empire.
The barbarians could not learn this technique.