When Oromë invited the Elves to Valinor, those who followed him on the Great Journey were called the Eldar, :374 while those who refused were called the Avari. The Eldar were divided into three clans−the Vanyar, the Noldor, and the Teleri. All of the Vanyar and Noldor reached Aman.
In the ancient days of the first age there were three hidden kingdoms of elves Doriath, Nargothrond, and Gondolin. All three of the kingdoms were shrouded in secrecy in one way or another from the dark lord Morgoth. His realm, far to the north was named Angband, and it was unapologetically out in the open.
In J. R. R. Tolkien's legendarium, the Elves or Quendi are a sundered (divided) people. They awoke at Cuiviénen on the continent of Middle-earth, where they were divided into three tribes: Minyar (the Firsts), Tatyar (the Seconds) and Nelyar (the Thirds).
Who is Legolas? Legolas is a Sindarin Elf from the Woodland Realm of Northern Mirkwood. His father, Thranduil, is the King of the Silvan Elves living in that realm, making Legolas the Prince of Mirkwood.
She was a royal Elf of both the Noldor and the Teleri, being a grandchild of both King Finwë and King Olwë. She was also close kin of King Ingwë of the Vanyar through her grandmother Indis. Galadriel was a leader during the rebellion of the Noldor, and present in their flight from Valinor during the First Age.
Elrond was a Peredhil,a half elven,with Noldorin and Vanyar blood from Idril daughter of Turgon who was a Noldor with a Vanyar mother,and Sundar blood from Elu Thingol of Doriath,and Mannish blood from the 3 houses of Edain:from Beren through Dior and from the houses of Hador and Haleth through Thor son of Huor of the ...
Arwen is one of the half-elven who lived during the Third Age; her father was Elrond half-elven, lord of the Elvish sanctuary of Rivendell, while her mother was the Elf Celebrian, daughter of the Elf-queen Galadriel, ruler of Lothlórien. She marries the Man Aragorn, who becomes King of Arnor and Gondor.
Thus, Galadriel's dark form in Jackson's The Lord of the Rings personified what would have occurred had the Lady of Lothlorien given in to temptation and taken the One Ring for herself. She would have succumbed to evil because the Ring was indomitable, even with her power.
Legolas never marries. The closest he gets is spending the rest of his life, as far as we know, with Gimli; they travel around Middle Earth for decades together, and eventually Gimli is given special dispensation to travel to the Undying Lands with his "friend" Legolas—the only dwarf ever to do so.
The three rings were Vilya, Nenya, and Narya. The rings Vilya and Narya went to Elven High King Gil-galad of Lindon, who entrusted Vilya to Elrond and Narya to Círdan, Elven lords of Rivendell and Mithlond, respectively. These rings were kept by Elrond and Círdan following the death of Gil-galad.
The ring was gifted to an Elven High-King and passed down through generations. Upon meeting Gandalf, an Elven descendant gifted him the ring to aid in his protection of Middle-earth.
As previously stated, Gandalf is a Maia and is therefore superior to Elves regarding power. Still, this isn't to say that an elf couldn't develop enough skill and power to defeat a Maia. As a bearer of one of the Three Elven Rings (Nenya), Galadriel would have an edge against Maiar like Saruman and Radagast.
The majority of her powers come from her Ring of Power, Nenya, the Ring of Water. The ring, also known by the names the White Ring and the Ring of Adamant, is one of the three Rings of Power given to the Elves of Middle-earth in the Second Age.
For those that haven't read Tolkien's work, it's easy to see why many audiences suspect Gandalf and Galadriel are in love. After all, many of their interactions in The Hobbit trilogy practically scream romance. However, their relationship remains purely platonic in Tolkien's source material.
Arwen probably got to know Legolas as her husband's friend and as the leader of the Elven colony in Ithilien. As Mary Tower points out, it is possible that they are distantly related, but it's nowhere stated.
Aragorn was a descendant of Isildur, who was a descendant of Elros. So, Aragorn did have Elvish blood in him. Granted, the Elvish blood was many generations removed, and for that matter, Elros had declined his bid for immortality. So, Aragorn's status as part Elf was severely diminished.
In terms of genealogy, Elros would be Aragorn's great grandfather with about 60 "greats." This makes Elrond Aragorn's great, great, etc. uncle, and since Arwen is the Lord of Rivendell's daughter, she and Aragorn are first cousins many times removed.
The Third Age. At the beginning of the Third Age, Elrond married Celebrían, daughter of Galadriel. They had three children: twin sons, Elladan and Elrohir, and a daughter, Arwen.
