Elrond and Elros were the twin sons of Eärendil. The Valar gave each brother a choice whether to be counted among the kindred of Elves or of Men. Elrond chose to belong to the Firstborn, and remained in Lindon with Gil-galad, where he became known as a healer and loremaster, but Elros chose to become a mortal Man, and became Tar-Minyatur, a lord of the Edain and the first King of Númenor.
Maedhros The Tall was one of the princes of the Noldor, the eldest of the Sons of Fëanor and head of the House of Fëanor for a time. For hundreds of years, he led the House of Fëanor against the forces of Morgoth but the Oath he and his six brothers swore to recover the Silmarils constrained him.
Among those of Melkor’s servants that have names the greatest was that spirit whom the Eldar called Sauron, or Gorthuar the Cruel. In his beginning he was of the Maiar of Aulë, and he remained mighty in the lore of that people. In all the deeds of Melkor the Morgoth upon Arda, Sauron had part, and was only lees evil than his master in that for long he served another and not himself. But in after years he rose like a shadow of Morgoth and a ghost of his malice, and walked behind him on the same ruinous path down into the Void.
‘The Wise among Men say: “We were not made for death, nor born ever to die. Death was imposed upon us.” And behold! the fear of it is with us always, and we flee from it for ever as the hart from the hunter. …”’
'None could have done this to you save the One. Therefore I say to you, Andreth, what did ye do, ye Men, long ago in the dark? How did ye anger Eru? For otherwise all your tales are but dark dreams devised in a Dark Mind.’
Nienna was an Ainu, one of the Queens of the Valar and one of the Aratar. She was the sister of Mandos and Irmo and had no spouse. Her part in the Music of the Ainur was one of deep sadness, from which grief entered the world at its beginning. She had dominion over the Halls of Nienna, which were on the western edge of Valinor, looking over the sea.