"Why didn't we know about this?!"
Uriah's expression was filled with shock and fear, and Tray was also looking in bewilderment at Elian.
They both know what this killing formation represented. It meant as long as Golden Iron Demon Clan or Elian know how to operate it, they were the kings inside the Iron Demon.
The Silver Iron Demon Clan and Bronze Iron Demon Clan can do nothing to shake their position as overlord, not before they found a way to overcome this low-grade-1 killing formation or invite a soul realm cultivator, which was also impossible.
They finally understand just why the Golden Iron Demon's position remains unshakable all these years, and why Elian didn't put them in his eyes before.
Elian simply answer without even blinking, "Only the Chief of each generation had the information about this Killing Formation called Ten Golden Pillar Swords, and only if some calamity struck the chief was allowed to disclose its information.