Ruler Xing Yun's Heart Of Evolution wasn't contaminated, but the threads came from the Heart of Evolution. The Dark Force was already in a bad state as it spread through the threads.
Also, the threads were extremely thin. It would be hard to remove the Dark Force from them.
By right, these strings were an extension of the Heart of Evolution so they shouldn't be so weak. However, this depended on what it was compared to.
Under the heat of the divine flame, even the toughest thing would melt, much less this thin line.
This was a test of Wang Teng's control of the divine flame. It was extremely difficult for him to control it with these strings.
Also…
Wang Teng carefully observed the Dark Force on the strings. His expression turned more and more serious.
He noticed that the Dark Force was dark red in color. It gave off a thick and bloody aura.
