What could Castle of Black Iron do when combined with the crystal ball controlling the temple's core?
First, if Zhang Tie wished, he could turn the entire temple into a vacuum, devoid of even a trace of air. In that state, he could breathe the air from Castle of Black Iron, while the Devil Race's Earth Knight would have to fight in a vacuum.
An Earth Knight's battles consumed an enormous amount of stamina and Battle Qi, and such immense expenditure likewise needed breathing to sustain it. How many hours could an Earth Knight who had to hold his breath and could not breathe endure high-intensity combat for—three hours, or five?
Second, what was the laziest method? It was for Zhang Tie to keep the temple at ultralow temperatures and in a vacuum while continuing to seal its doors. Under those circumstances, Zhang Tie would not need to pay any attention to this Devil Race Earth Knight, nor would he need to fight the Devil Race knight. He only needed to enter Castle of Black Iron, then come out two days later to collect a dead fish.
The Devil Race baron's remote-sensing communication crystal had already been destroyed, while his space-teleportation ring was in Zhang Tie's hands. Under such circumstances, the Devil Race baron was merely a turtle trapped in a jar.
Thus, from the instant the temple doors closed, the Devil Race baron's fate had already been decided.
The Devil Race baron's defeat lay in his greed, arrogance, and ignorance of the trump cards Zhang Tie could play.
The reason Zhang Tie had not chosen either of those methods was that this opportunity was likewise once in a thousand years for him. Here, he had to seize it and squeeze every last bit of value from the Devil Race