These seven were the second reason for the arrogance and confidence of the Imperial members beside their unity, the Elders of the Nie Family.
Their authority gathered together could place a veto on the decisions of the Imperial Throne, and served the purpose of the counterbalance against rampant authority of a rogue sitting monarch.
The problem was that Nie Xiwang took the throne by force, ignoring tradition, as well as her identity as an illegitimate child, which turned the very conservative Council of Elders unanimously against her.
This practically killed off her already weak power over the Imperial Family, as she would be vetoed from punishing any member unless she could prove their offense with undeniable evidence and witnesses to the Council of Elders.