All the members of the Dark Gold Treaty were bound by a very powerful contract to not leak anything to a third person. If they tried to do it or someone forced them to get the information from them, this contract would immediately take effect and would prevent the information from being leaked.
There were various contracts which had this effect of information leakage prevention. But for powerful people, there were always ways to bypass this. But the contract that the Dark Gold Treaty used was extremely powerful and even for level 600 plus peak powerhouses, these contracts were almost invincible.
But as a generational hater of the Dark Gold Treaty, Esfe had managed to create a way with her unique powers to do just that. She was one of the rare few people in this world who had the skills to even bypass the best contracts that the Dark Gold Treaty could use.