By the time Ye Qingtang arrived at the Second Domain in her previous lifetime, the Fiendcelestial Tomb had already been open for decades. It wasn't a secretive affair at all. Almost everyone in the mainland knew about it and would talk about it.
Ye Qingtang had been hiding around many places, so she naturally heard the discussions about the tomb.
The Fiendcelestial Tomb could never be opened using external forces. Even if an Emperor level person tried to forcibly open it, there would be a counter-effect.
If anyone tried to forcibly open the tomb, just like the muscular man from the Falling Water Pavilion, there would only be one outcome… and that was death.
The only way to open the Fiendcelestial Tomb was for the Night Soul Beast to personally open it.
The Night Soul Beast was the protector of the Evil Soul Forest and also the Fiendcelestial Tomb.
However, only Ye Qingtang knew about it.