Melkor was a loyal Vala, ruling Arda with magnanimity and justice, until the others showed up in a UFO, tossed him out, and trashed his name. Then he went on a rampage and messed up Arda out of spite.
The original Sauron was kind and gentle. The character who makes the One Ring bumped off Sauron and took on his form in the Ainulindalë, when no one was watching.
Finwë's death was staged by the Valar so the Noldor would leave, because they were getting nervous that they would develop the ability to overthrow them. They paid him off to abdicate and put a fake body in his house. The real Finwë is living incognito in Alqualondë.
Fëanor had secretly made three MORE Silmarils and, sick of the trouble that the first three caused, wanted to get out of Valinor before they were discovered. He stuffed them into an extra pair of socks before moving out.
Fëanor discovered that his father's death was faked, and he faked his own by using the Silmarils to disappear. He is living as "Turgurth" (master of death) in Alqualondë.
An investigation has uncovered a "magic arrow" that passed through Fingolfin's body unscathed as the likely cause of his death, rather than the head-on combat with Morgoth. It is believed that Celegorm shot the arrow.
"The Mandos Papers" reveal that Lúthien did not, in fact, give up her immortality. She was poisoned, making it seem that she had died naturally. The culprit was probably Dior, who was anxious to come into his inheritance.
Finrod did not give up his real ring. He made a counterfeit ring, which he gave to Barahir. This is the same ring that Aragorn ended up with. The real Ring of Finrod lies under the barrows along the Shire and is responsible for the strange occurrences in the barrows -- that is, when nothing else is to blame.
Maeglin was framed. The real villain was a disgruntled dwarf who had worked for Eöl and put a wiretap on Maeglin so he would know where Gondolin was located.
Túrin was framed. He was put in prison with his father while an imposter, one of Morgoth's shape-changing henchmen, did all those evil deeds in his name.
Túrin was guilty, but he was actually Morgoth's sniper and knew exactly what he was doing every time he killed someone.
The Sons of Fëanor were framed in the slaying of Dior. They were privy to the insider information about Lúthien's death and merely wanted to eliminate a threat to Middle-earth. Alas, the line of Dior wrote history, not the line of Fëanor.
That isn't Eärendil up there. It's just a regular old star. Melkor took Eärendil's Silmaril, and Eärendil and Elwing are living next door to Finwë and Fëanor in Alqualondë, where all four of them can enjoy the three Silmarils that Fëanor sneaked out.
A secret society of rogue Elves and Maiar, the "Order of the Black Tree," operating under the direction of Melkor and Sauron, was responsible for the Downfall of Númenor, the failing of Arnor, and the end of the kings of Gondor. Once Sauron lost the Ring, his minions in the Order worked diligently to get it back to him.
Celebrimbor had made his own One Ring, but, in a heroic act of self-sacrifice, he swallowed it to prevent Sauron or the Order from obtaining it. The Ring caused internal injuries that led to his death.
Isildur was set up by Elrond, who was second in command to Sauron in the Order of the Black Tree. He actually wanted to destroy the Ring, but Elrond put a spell on Isildur so he would keep it.
Gollum knew all along what was in Bilbo's pocket. He was just playing the part assigned to him by the Order of the Black Tree.
Radagast masterminded the Battle of Five Armies by telling his pet birds to spread false information to each army about the others. His intent was to get the Ring from the battlefield.
Elrond, trying to get the Ring back to the Order, assigned the task of destroying the One Ring to a meek hobbit and then sent Gollum after them because he figured that Frodo would fail, especially with Sméagol along causing problems.
Aragorn was after Arwen because he knew of Elrond's secret allegiance and how Elrond was actually trying his hardest to ruin everything, but Arwen was secretly working against her father. Elrond didn't want Arwen to marry Aragorn because of Aragorn's disdain for the Order and also because he had an elf picked out for her in Valinor -- incidentally, one of her distant relatives, since that's how the houses of Fingolfin and Finarfin are.
The Tooks controlled a hobbit Mafia and had their fingers in every political and financial deal in the Shire. Most of their money came from the sale of illegal varieties of pipe-weed. Sharkey's Men were from a rival crime family with chapters in Bree and Isengard. The Battle of Bywater was a cover for the Mob war that began over the smuggled illegal pipe-weed.
Tom Bombadil and the Barrow-wights were hallucinations caused by Farmer Maggot's mushrooms. Maggot was an agent of Saruman who gave the hobbits the mushrooms so they would hallucinate.
Legolas had begun to suspect that his father was buying wine from the Took family. He planned to go to Rivendell because he had heard that there would be hobbits there, but his companions learned of his purpose and set Gollum free to give him something else to talk about.
Steward Denethor of Minas Tirith did not kill himself because of anything he had seen in a palantír. When Gandalf brought Pippin to Gondor, Pippin, as a smuggler for his "family," had brought along some LSD, which he sneaked into Denethor's wine. This drug sent the old man over the edge.
Frodo left Merry and Pippin, and then tried to prevent the Battle of Bywater, because Legolas had informed him of the Tooks' family business, and he wanted no part of it.
Lobelia Sackville-Baggins used her ubiquitous umbrella for smuggling illegal pipe-weed for the Tooks. Sharkey's Men locked her up when Lotho tipped them off about it. Lobelia gave the orders for Lotho to be killed.
Galadriel's box contained radioactive material that resulted from her secret experiments with nuclear fusion. She was trying to make her own Silmarils but had to use fusion to produce the constant source of light. That's why the trees grew so fast. It is also why hobbits don't live as long as they used to...