After Zhou Feng discovered that Bai Wuyi's physical body wasn't very strong, he immediately attacked crazily to trigger the passive Armor-Piercing Spear.
As long as his attacks connected, the armor on Bai Wuyi's body wouldn't be of any use.
Even other defensive methods wouldn't be able to block the passive Armor-Piercing Spear's effect.
The strength bonus from the passive Fighting Spirit increased Zhou Feng's power, which was then transmitted through the passive Armor-Piercing Spear's effect.
What's more, the passive Adaptive Shell's damage reduction effect had been maxed out, and Zhou Feng could withstand Bai Wuyi's attacks.
Coupled with his Self-Healing Constitution and Whetstone, he was able to wear down Bai Wuyi.
Zhou Feng's physical body resisted everything, be it melee or ranged attacks, and he vanquished them with brute force.
On the other hand, Bai Wuyi seemed to be on the defense.