The degree of compatibility between the black substance and Zheng Yichen was incredibly high, reaching an extreme level that allowed his Sword Nourishing Technique to be maximized.
In summary, as long as it's sword-type weapons, within an extremely short time, they can reach 70% of their maximum strength, and the remaining part has to be slowly nurtured.
Once the true limit is reached, the rapid increase in strength will gradually slow down, marking the stage of breaking through the limits.
Before reaching the boundary of breakthrough, it's like some strong adhesive, initially reaching a high strength rapidly, with the remaining strength only reaching the highest level after some time.
The influence of the Sword Nourishing Technique made the weapon he formed from black substance more resilient, fundamentally avoiding the issue of not using black substance in high-end battles.
