The Beast Soul Realm was a Small World belonging to an Elder Heaven-Devouring Wolf. The wolf had been incredibly powerful, even stronger than Feng Lingzi and the Young Leader were now. It had been every bit as strong as Po Qiong's former master, Fengyunzi. It had also survived the final tribulation, and traces of that tribulation still lingered in Beast Soul Valley and throughout the Beast Soul Realm—far more concentrated and pure than the remnants in the Lingxiao Realm.
The Beast Soul Realm was saturated with the aura of tribulations. If a cultivator underwent a tribulation there and it was powerful enough, it could resonate with the lingering tribulation aura, greatly amplifying its might.
When Ling Tian underwent an Ancient God-level tribulation in the Lingxiao Realm, he had resonated with the tribulation aura left behind there. The aura in the Beast Soul Realm was more concentrated and pure than the Lingxiao Realm's, and this Ancient God-level tribulation was far more powerful than his previous one. It was only natural that it would resonate with the tribulation aura in the Beast Soul Realm.
Once the resonance began, his Ancient God-level tribulation rivaled the Saint God-level tribulations many cultivators faced. Lightning raged across the sky, its crackling never ceasing. A violent, destructive aura filled the air, as if the world were coming to an end. Cultivators in many distant places sensed it.
Although Ling Tian and the others had been hunting cultivators around their temporary base, many others were still watching them from far away. So when the Outer Realm Cultivators appeared and launched their sneak attack, those observers saw it all. They immediately sent word back, and countless cultivators converged on the area. They had stayed on watch nearby without leaving, so they felt Ling Tian's tribulation all the more clearly.