Zheng Yichen's remaining trump cards were ineffective when he brought out the Heaven-Slaying Sword fragment.
What's crucial here isn't the Heaven-Slaying Sword itself, but the time technology related to the Boundary Breaking Organization.
The Heaven-Slaying Sword's destructive power... well, it's just that. At least here, the effect of Destruction Power isn't apparent; only the Oblivion force can affect the Dusk environment.
Dusk itself also has resistance to Oblivion, or rather, this environment is a blank area capable of bearing Oblivion. This environment is similar to the Outer Realm, so the Oblivion force's presence doesn't bring much impact.
Thus, the Destruction Power generated by World Destruction is not significant.
However, Zheng Yichen is quite strong right now, carrying the pain feedback brought by those Freezers, and the Oath Power adds an extra enhancement to this feedback.
