The Council

The Council is apparently the head of a conspiracy to establish a new Storm King empire. To this end they have created their own fake Heterodyne and gotten a mole into Castle Heterodyne.

The general idea seems to be to recreate the "fairy-tale" of the Storm King marrying a female Heterodyne Heir, which according the the Storm King Opera is prophecied to bring stability to Europa.

They are probably part of the Knights of Jove, and may or may not be the same as The Order mentioned in Sturmhalten.