It had been nearly an hour since the black wind vortex had appeared. Not a single creature came out of it, and the masters didn't dare to come any closer either. Breaking the portal vortex was relatively easy—they could have destroyed a spirit master's portal before its owner summoned reinforcements.
However, this vortex was significantly different from ordinary soul master portals. The energy of this portal came from pure evil energy and thirst for blood. In addition, the demon king has the ability to suck human souls and turn them into his own power.
Let alone destroy it; if they were to get close to the black wind vortex, their souls would be sucked in and separated from their bodies. Thanks to that frightening cause, all the soul masters stood behind the first layer of defense and released their soul forms.