LOTR: How Are Arwen And Aragorn Related?

gamerant.com:

The romance and marriage of Arwen and Aragorn are unique in a variety of ways. The first and most obvious way is that Arwen is an Elf and Aragorn is a Man, which is not something that regularly occurs in Middle Earth. The next and perhaps less obvious, way that Aragorn and Arwen make a unique match is that Arwen is Aragorn’s aunt. However, because Arwen is also so much older than Aragorn, it is a relationship that spans not only race but also generations.

But how many generations? For Arwen, it would be two. Eärendil is the common ancestor between Arwen and Aragorn, and Arwen’s father is Elrond, Eärendil’s son. However, the unique thing about Eärendil is that he is not Elfkind, he is a man, which is why Elrond is often referred to as Elrond Half-Elven. Indeed, in order to understand Arwen and Aragorn’s relationship, it is helpful to know more about their common ancestor, Eärendil, and his wife, Elwing.

LOTR: What happens to elves after they die?

Elwing herself played a crucial role in the recovery of the Silmarils, jewels whose light resembles the light from the ancient Trees of Valinor. Elwing escaped from Doriath with a Silmaril, married Eärendil at the Mouths of Sirion, and went into the East to Valinor. The recovery of the Silmarils from various forms of evil drive many of the events of the First and Second Ages, including the tale of Beren and Lúthien.

Eärendil was a great mariner, and his ship is adorned with the last Silmaril which Elwing recovered from Doriath. Doriath is a forest, most famous for being the abode of Thingol and Melian, Lúthien's father and mother. In fact, it is the light of Eärendil that Galadriel gives to Frodo in Lothlórien when the Fellowship passes through after the events in the Mines of Moria.