As the Undead Divine King, an ally of Zhou Tian, although it's unclear if he has any hidden trump cards, it was already commendable that he could perform the way he did under the theoretical circumstances at that time.
Only that Space God King, although his performance at that time could be described as extremely strong, Zhou Tian still felt that during their battle, the opponent hadn't given it his all.
It's easy to understand why Zhou Tian would have that thought.
After all, the Space God King Zhou Tian and his allies were facing was an old-school God King in the Divine Realm. Not to mention that the spatial rules he cultivated gave him power far exceeding typical God Kings, even if he were just an ordinary God King. If he had developed over billions of years in the Divine Realm, Zhou Tian would never believe he didn't possess some hidden trump cards.
