For nearly a thousand years since the Kingdom of Arnor had been destroyed by the Witch-realm of Angmar, its surviving descendants had lived in deep secrecy, rarely revealing their identities. Even when they needed to trade with the residents of the Shire or Bree-town, they usually appeared as wanderers.
The reason was their fear that their ancestors' enemy would hunt down and extinguish what little remained of their bloodline.
Isildur's great enemy was, of course, the Dark Lord Sauron. During the War of the Last Alliance, besieged by the alliance of Elves and Men, Sauron had been forced to leave Barad-dûr in the hope of breaking the siege and reversing his side's decline. His entry into the battle had indeed dealt the alliance a devastating blow: the moment he appeared, he personally slew its two High Kings.
Gil-galad, High King of the Noldor, and Elendil, High King of the Númenóreans, had both fallen in that battle. Sauron had also crushed Elendil's sword, Narsil, beneath his foot.
At that point, the outcome of the war had seemed clear. Yet at that moment of greatest peril, Isildur had used the broken Narsil beside him to cut off the finger on which Sauron wore the One Ring. Deprived of the One Ring, Sauron had suffered a devastating injury and exploded on the spot, while Isildur became the battle's most outstanding hero.
It was easy to imagine how deeply Sauron hated Isildur and his descendants after suffering such humiliation. He had already been locked in a bitter struggle with Gondor for some two thousand years. If he learned that any bloodline of the Kingdom of Arnor remained, he would likely send his most capable servants to wipe out these Dúnedain.
The Dúnedain living in seclusion knew this as well, so they went about their