As a result, unable to summon too many of his Beastman subordinates, Zhou Tian simply decided to face those dozens of Demigods alone. Although the collective Strength of those Demigods was greater than his own, combat doesn't work in a way that ten beings with a Combat Power of one could amount to a single entity with a Combat Power of ten. Otherwise, battles would just be a matter of amassing numbers, and there wouldn't be such a significant effect from the presence of a master.
Even if Zhou Tian's combined Strength was inferior to that group of Demigods, all he needed to do was ensure his Strength was greater than any individual Demigod. Since he was on his own, he had the advantage of greater flexibility, and without engaging in a Hard Fight with his opponents, he could defeat them in Guerrilla Warfare, sooner or later.
Given the circumstances at that time, once Zhou Tian took action, it was natural that he quickly became a substantial threat to that group of Demigods.
