"According to the young lady, the rootless ocean doesn't belong to Qing-Yun realm, and she didn't tell us where it came from. She only said that the rootless ocean has the ability to travel across the laws of the realm.
Of course, only Lady Zhao could do such a thing. If it was someone else, they wouldn't even know where the rootless sea was. Even if they found it, they wouldn't be able to make use of it.
