"Sealed within this primeval universe is the passageway that leads to the Ancestor God's universe. To the people in this universe, this passageway is no different from the entrance to hell." Godly Monarch River of Forgetfulness's tone seemed to have a tinge of regret and retrospection. He was probably recollecting the massive battle following the Ancestor God's invasion from so many years ago.
Back then there was the Dao Originator Celestial Thearch to hold down the fort, but now… the seemingly thriving Martial Dao was actually in decline. The Godly Monarchs were few in number, and the Godly Monarchs who received the Dao Originator Celestial Thearch's heritage were either dead or severely injured.
If the passageway was opened, it would lead to unthinkable consequences.