It is the ruling body of 24 beings who have achieved the correct illumination and elevation in the Eternal Wisdom, which governs the Confederation of Worlds in the Milky Way. It is also responsible for planning aid missions such as Mission Rama.
The seat of this Council is currently in Morlen ( Ganymide, one of Jupiter's moon ) in the Crystal City.
They have participation with the council of the 9 of Andromeda forming a council of 33 members representing the Great White Brotherhood of the Star.
Note: they are mentioned on the Christian bible, Revelations 4:4:
"Around the throne were twenty-four thrones, and on the thrones I saw twenty-four elders sitting, clothed in white robes; and they had crowns of gold on their heads".
The list of the 24 Elders of the Milky Way