Advisory Council

When Horaeri, The First Emperor created the Fenixian Empire he recognised he couldn't rule completely alone. So he created an advisory board made up of his friends who had accompanied him to the Shautane Grotto and were now the leaders of their families.
This group of advisors continued for the first few years, as the empire settled down and building the City of Fenixia began. Horaeri realised the importance of keeping records of his actions, and wanted to leave that as part of his legacy. So he created the archive as part of the Emperor's Palace, and the position of Archivist. He gave the role to his childhood friend, and made him part of his advisory council.
Over the generations, while the individuals changed, the make-up of the advisory council didn't. The six members (five Family Parents and the Archivist) advised the emperor on all matters within the empire. At its heyday, it controlled the emperor, rather than the other way round.
The end of the council
When Fiere, The Final Emperor passed away, the family parents decided to share the rule between themselves. So they formed their own council, excluding the archivist, as they didn't them to have a say in how they ran things. Technically the advisory council was never disbanded, but without the emperor it's function has been superceded by the Parent Council and no longer meets.