“23. THE SELF-BORN WERE THE CHHAYAS, THE SHADOWS FROM THE BODIES OF THE SONS OF TWILIGHT. NEITHER WATER NOR FIRE COULD DESTROY THEM. THEIR SONS WERE (SO DESTROYED).
The First Root-Race, the “Shadows” of the Progenitors, could not be injured, or destroyed by death. Being so ethereal and so little human in constitution, they could not be affected by any element – flood or fire.
But their “Sons”, the Second Root-Race, could be and were so destroyed.
The bulk of the Second Root-Race perished in this first great throe of the evolution and consolidation of the globe during the human period.
Of such great cataclysms there have already been four. And we may expect a fifth for ourselves in due course of time.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 