Elves are one of the many types of living being in JRR Tolkien’s stories.
Elves were the first to be “awaken” at the beginning of times. Here is the legend. Written by the editors on the Lord of the Rings Fandom Site:
According to a legend of the Elves, the first Elves were awakened by Eru Ilúvatar near the bay of Cuiviénen. The first Elf to awake was called Imin (“First”). Next to him lay Iminyë, who would become his wife. Near where Imin woke, awoke Tata (“Second”) and Tatië, and Enel (“Third”) and Enelyë.
Imin, Tata, and Enel and their wives joined and walked through the forests. They first came across six pairs of Elves, and Imin, as eldest, claimed them as his people, and woke them. After a short time Imin and his people, together with Tata and Enel, continued their journey. Next, they came across nine pairs of Elves, and Tata as second eldest, claimed them as his people. After a short time the now thirty-six Elves continued their journey. Then they found twelve pairs of Elves, and Enel, as third eldest, claimed them as his people.
For many days the now sixty Elves dwelt by the rivers, and they began to invent poetry and music.
Finally they set out again, but Imin thought to himself that since each time they had found more Elves and his folk was least in size, he would now choose last.
They came across eighteen pairs of Elves, who were watching the stars, and Tata and Enel waited for Imin to claim them for his people, but Imin told them he would wait, so Tata added them to his folk. They were tall and had dark hair, and they were the fathers of most of the Ñoldor of later times.
The ninety-six Elves now spoke with each other and invented many new words, but then they continued their journey. Next they found twenty-four pairs of Elves, who were singing without language, and again Imin was offered the choice, but refused. Therefore Enel chose them as his people, and from them came most of the Lindar or singers of later times.
And the hundred and forty-four Elves now dwelt long together, until all had learned the same language, and they were glad. But then Imin said it was time to seek more companions for him, but most of the others were content and did not join him. So Imin and Iminyë and their twelve companions set out alone, and they searched long near Cuiviénen, but never found any more companions.
And because all Elves had been found in groups of twelve, twelve became the number they counted with ever after, and 144 was for long their highest number, and in none of their later tongues was there therefore any common name for a greater number.
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Most other living creatures are descendants of the elves.
Elves have an immortal life so they live forever. However, some elves chose to live with a man over an elf and have “half-elven” children. The “half-elves”, have a choice to live an immortal live, like usual, or a mortal live. Even if they chose a mortal life, they still can live for up to 1000 years!