2. About the Half-Elvin race If you are an half-elven, you are part man and part elven. When you are a born, you get to chose to be either be like a man or like an elf. An example is Elrond. He is a half-elven who chose to be an elf.
3. How the half-elven race started Beren and Lúthien was the first man/elf couple. They lived in the first age. They had a son named Dior, who took over the Sindarin kingdom after his father’s tragic death and his mother’s passing. He married Nimloth, another elf, and had three kids, Elwing, Eluréd and Elurín.
4. Elros Elwing married Eärendil and had two kids, Elros and Elrond. Elros became the great greatgreatgreatgreat Grandpa of Aragorn, who is something like 1/164th elvish.
5. Elrond Elrond is the second of the two sons of Elwing and Eärendil. Unlike his brother, he chose to be an elf instead of a man. So he lived though all three ages. He married Celebrían and had three children, Arwen, Elladan, and Elrohir.