C2579 Test
It was probably because the Heavenly Slaughter Sword already recognized Feng Zhi as its master, and even though the power was tyrannical, it was merely preventing the wound on Feng Zhi's hand from healing, and did not enter her body to cause trouble.
However, Feng Zhi could feel that if it was another person who was injured by a Heavenly Slaughter Sword, even if it was only a small wound