The Nazgûl (Ringwraiths) were created by the Dark Lord Sauron, who gave nine Rings of Power to powerful mortal Men, including kings and sorcerers, in the Second Age. These rings enslaved the bearers to Sauron's will, extended their lives unnaturally, and eventually faded their physical bodies, turning them into invisible wraiths bound to the One Ring.
The Nazgûl or Ringwraiths (Quenya plural: Úlairi) first appeared in the Second Age. The Dark Lord Sauron gave nine Rings of Power to powerful mortal men, including three lords of the once-powerful island realm of Númenor, along with kings of countries in Middle-earth.
The Nazgûl (Black Speech for "Ringwraiths"), also known as the Nine Riders or Black Riders (or simply the Nine), were Sauron's "most terrible servants" in Middle-earth. They were mortal Men who had been turned into wraiths by their Nine Rings of power.
He is one of the Nine Men that became Nazgûl (Ringwraiths) after receiving Rings of Power from the dark lord Sauron. His ring gives him great power, but enslaves him to Sauron and makes him invisible. As a wraith, he had once established himself King of Angmar in the north of Eriador.
Sauron began his days as Mairon (“the admirable”), a powerful Maia—spirits who came to Arda to help the Valar shape the world. (Other Maia include Gandalf and Saruman.) He was a pure and orderly being in the beginning, who studied the craft of forging. But he grew selfish, and eventually aligned himself with Morgoth.
Morgoth is the devil, and Sauron is a servant of the Valar who chose to follow Morgoth. Sauron is more like a fallen angel. The mythology is different, but the Christian principles are definitely all throughout the books! He's a fallen Maiar which is kind of like an angel sort of.
As a Maia, Gandalf was an angelic being in human form, in service to the Creator (Eru Ilúvatar) and the Creator's 'Secret Fire'. He took on the specific form of an old man as a sign of his humility. His role was to advise but never to attempt to match Sauron's strength.
It's possible that Gollum's prolonged search for the ring allowed it to maintain a significant power over him, suspending his aging process. In contrast, Bilbo's exposure to the ring's influence waned after he willingly (mostly) relinquished it, allowing his aging to resume more noticeably.
If Gandalf had stayed dead after his sacrifice in The Fellowship of the Ring, then his demise would be the saddest in the trilogy, but since he came back, the saddest single death scene of all three movies goes to Boromir's.
It's not the years; it's the mileage. Gandalf isn't a Maia in the same way Sauron is. He was sent to middle earth as an old man, so his body is much more real than Sauron's “raiment”. He can't use his power to the same extent, he can't change his forms at will.
Gollum came from the river folk. He was shown as a hobbit in The Two Towers. The ring, time, centuries living under a mountain and steady diet of goblin babies changed his appearance, but not his past.
But at the Council of Elrond, Gandalf very specifically says he fought all nine. He drew four of them off when he fled northward at dawn; "This helped, a little, for there were only five, not nine, when your camp was attacked."
After he was attacked by the orcs, they transported his lifeless body to Mordor at Sauron's behest. Sauron revived Isildur with one of the nine rings, and then tortured him until his spirit was broken and he became a Nazgûl.
Fellbeasts are monstrous, wyvern-like creatures that were bred by Sauron to be steeds for his lieutenants, the Nazgul. They were not truly dragons, but rather creatures from an older time long past in Middle-Earth. Sauron bred them as a challenge to the Great Eagles, their good-aligned counterparts.
The townsmen's arrows and spears proved useless against the dragon's armoured body. The thrush told Bard the Bowman of Smaug's one weak spot, a bare patch on the dragon's belly. With his last arrow, Bard killed Smaug by shooting into this place.
In the books Bilbo hadn't even come close to catching up with his biological age until after the Ring was destroyed. (And since Gollum was destroyed with the Ring, there wasn't any chance for his age to catch up with him.)
Instead, we have to consider that Sauron, the original owner, is not human, but has a quasi-divine status. Therefore ownership of the Ring is subject to Divine Law. With this precedent in mind, many of the ambiguities clear up nicely. After numerous transfers by violence and trickery, Frodo is the true owner.
Tolkien's description of Gollum conforms to a Catholic – and Thomistic – account of envy, which is a “sadness of the soul”; and it is Gollum's unbearable sadness and his unquenchable desire for the one Ring that marks his character.
Sauron's rise to power in the Second Age is portrayed in the Amazon prequel series The Lord of the Rings: The Rings of Power. He first appears disguised as the non-canonical human character Halbrand, and then in the second season as Annatar (a canonical alias of Sauron), both played by Charlie Vickers.
Gandalf does not WANT to touch the ring. Just as Galadriel resists the temptation to take it when Frodo offers it to her willingly. And all this because "Power Corrupts". Sauron and the Ring are allegories for the corruption that inevitably arises when too much power is concentrated in one place.
Sauron's original name was Mairon. He was the mightiest Maia of the Vala Aulë the Smith, and learned much from Aulë of smithing and handiwork, becoming a great craftsman and "mighty in the lore of" Aulë's people. He was among the most powerful Maiar overall.
Melkor is the most powerful of the Valar but he turns to darkness and is renamed Morgoth, the primary antagonist of Arda. All evil in the world of Middle-earth ultimately stems from him. One of the Maiar of Aulë betrays his kind and becomes Morgoth's principal lieutenant and successor, Sauron.
Why does Gandalf say he is Saruman when he comes back as 'Gandalf The White'? It was just a figure of speech, one might almost say; he was Saruman in the sense that he is now the head of the order or that he would be the good Saruman.