The Moderator or Moderators (they have been referred to as singular or plural on instances) are considered "guardians" or "peacekeepers" in the universe. In the reason for Kämpfer on Earth to fight, the Moderators proposed that in order for a two-sided cosmic battle between "Red" and "Blue" to stop, they had others to fight in their stead. Also that the individual Kämpfer was to be caught to speed of the contest and to give advice they used Messengers . Unfortunately as the story implies, the Moderators' job as guardians or as the supreme authority(es) see any one not a moderator are made to do what they wished without telling the reasons behind them. This led to Shizuku Sangō to rebel against them and therefore led to the other three to cease the fighting. This made a problem of the potential of the cosmic battle to return. Not only that it was a breach of their authority that had to dealt with.
To solve the dilemma, they had Kaede Sakura as their instrument and representative to squash the rebellion. Also that she has the power to make Kämpfers for her mission thus creating the four White Kämpfers . In the Kämpfer für die Liebe, its revealed that "Kaede the Moderator" and the "normal Kaede" are split personalities in the same body though the latter has no memory of the former.