From Wikipedia:
The “Übermensch” is the being that overcomes the “great nausea” associated with nihilism; that overcomes that most “abysmal” realization of the eternal return. He is the being that “sails over morality”, and that dances over gravity (the “spirit of gravity” is Zarathustra’s devil and archenemy). He is a “harvester” and a “celebrant” who endlessly affirms his existence, thereby becoming the transfigurer of his consciousness and life, aesthetically. He is initially a destructive force, excising and annihilating the insidious “truths” of the herd, and consequently reclaiming the chaos from which pure creativity is born. It is this creative force exemplified by the Übermensch that justifies suffering without displacing it in some “afterworld”.
This describes the people involved in StartVI. They are the lightning from the dark cloud.