Ageless

There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
Genesis 6:4

These sons of the Nephilim were still giants by Genesis standards, but hardly remarkable when compared with today's athletes. In the eyes of the nomadic farmers of the time, these men would have seemed 12 foot tall. Extraordinary specimens though they were, their life expectancy was short. They were born with "hero" indelibly stamped on their foreheads, and let's be honest, nobody ever claimed they were mental giants.
It is a little-known fact that the offspring of these giants did not age like their contemporaries. They had no supernatural powers nor superhuman strength -- they were still mortal. Most of them perished in the flood. Some survived for hundreds of years. There are even a few still alive today, but more by sheer luck than any uncanny survival instincts.
The activities of these few remaining ageless ones have been wisely ignored by mainstream human history. After living for five thousand years without making a significant difference to anything or anyone, any reasonably intelligent being should have succumbed to suicidal ennui. Draw your own conclusions.

I can feel a short story coming together. It's about two brothers, Neville and Ralph (or Neffi and Raffi) and their long term feud.