>>5107628911. In Midrash Bereshit Rabbah (23:3), it is said that Naamah, the daughter of Lamech (a descendant of Cain), became Noah’s wife.
If this is true, then Cain’s lineage could have been preserved through her.
2. After the Flood — Numbers 13:33:
"...and there we saw the giants (Nephilim), the sons of Anak, from the Nephilim tribe; and we seemed to ourselves like grasshoppers in their eyes..." This was said by the spy of Moses, who returned from Canaan. In other words, the Nephilim appear again many generations after the Flood.
3. According to Book of Enoch some of the Nephilim or their souls survived the Flood — in the form of demon spirits, “wandering spirits” that trouble humanity. Their fathers — the fallen angels — were imprisoned in the abyss, but their offspring remained in some form.
4.In Gnostic teachings, it is often asserted that Cain’s lineage survived the Flood precisely because it did not come from “ordinary” humans, but from a special spiritual origin—connected to Samael, Satan, or the Demiurge, depending on the particular Gnostic school.
Cain’s lineage, in this understanding, is the “line” or “seed” of the Demiurge, distinct from the true spiritual humanity that originates from the higher divine sources (the Pleroma).
Therefore, this lineage is not subject to destruction by the Flood, since the Flood is a punishment and purification for the “material” or “false” humanity. However, Gnostics believe that Cain’s line is precisely a lower entity that exists “beyond” or “above” this punishment. In some versions, Cain’s lineage moved into the underworld or merged with the Nephilim and continued its existence “behind the scenes” of history.
