Arathorn II is the father of Aragorn in Tolkien’s history of Middle-earth.
Arathorn II was the sixteenth Chieftain of the Dúnedain of the North. He married Gilraen, and their son Aragorn was born in 2931 of the Third Age. Arathorn died when Aragorn was only two years old, killed by Orcs while hunting with the sons of Elrond.
After Arathorn’s death, Aragorn was raised in Rivendell under the protection of Elrond. Elrond kept Aragorn’s royal ancestry secret during his childhood and gave him the name Estel, meaning “Hope.” Aragorn later became a leader of the Dúnedain and an important member of the Fellowship of the Ring.
Isildur and Elendil were ancestors of Aragorn many generations earlier, not his father. Eärnur was the last king of Gondor before the line of kings ended, so he also belongs to a different part of the genealogy.