I'm curious as to why Sauron is the only being/person shown wearing the One Ring who does not become invisible?
Isildur, Gollum, Bilbo, Frodo, and Samwise all become invisible while wearing the One Ring.
Why didn't Sauron become invisible while wearing the one ring?
I became interested after reading Pearsonartphoto's question asking what effect wearing the One Ring would have had on other beings.
The Ring made its wearer invisible by shifting them mostly into the Unseen world. Gandalf told Frodo:
You were in gravest peril while you wore the Ring, for then you were half in the wraith-world yourself.
Gandalf also stated:
if [a mortal] often uses the Ring to make himself invisible, he fades: he becomes in the end invisible permanently, and walks in the twilight under the eye of the dark power that rules the Rings.
But Sauron already lived in that world as a Maia - his body was something deliberately constructed. Sauron was naturally pure spirit, not a hybrid like mortals or Elves and Dwarves. Since his presence in the mortal world was in effect a construct of his own, not him himself, it was not shifted into the Unseen world.
I was always under the impression that Sauron as the master of the One Ring and partial creator had much more access to the true powers of the ring. Invisibility seemed to be a very minor power that actually seemed to be drawing the wearer of the ring into the spirit realm. Sauron already seemed to have some mastery over the spirit realm and therefore wouldn't be subjected to becoming invisible unless he decided to.
It was my understanding that the One Ring was built FOR Sauron. Everyone else got a pale reflection of what it could do. Sauron had full control over it and was capable of using it to do several different things. The others who have it did not have any control over it and so they a) had no control over how the ring behaved for them and b) the ring would begin to control THEM. In essence the ring is still working for Sauron, even when he is not wearing it.
Sauron doesn't turn invisible because he is above the material world. He is of the beings that helped make it.
You have Eru Ilúvatar who if you were to compare to Christianity, would be God. You have the Ainur who are equivalent to angels for all intents and purposes. The Ainur split into two groups, the Valar (The greater of the two) and the Maia (The lesser spirits). I say they can be called angels, but the Valar might even parallel the Greek gods.
Sauron is a maia, just like Gandalf, Saruman, the Balrog, etc. The Ring was created by him as a means to control the other rings he offered to the Elves, Men, and Dwarves. He had complete control over the One Ring because he was its creator and master. I imagine any Maia would have had the abilities or know-how to demonstrate some form of control with the ring, but the theory never gets tested, as Gandalf is too afraid to use it. (We can only speculate that he was only too weak to handle it in his human form, but maybe even Olórin — Gandalf as a Maia, not a man — could have been corrupted.) We can also only speculate that Tom Bombadil, the only potential Ainur to have donned the ring besides Sauron, was even a Maia to begin with.
But Tom Bombadil did clue is into one thing, and that is that not ALL beings were drawn by its corruption, thus leading me personally to believe he was either Eru himself, or that if Gandalf had been in his true form, he would not have had problems with the Ring. As a manifestation of man, perhaps he was more prone to be corrupted. (A trait we see mirrored in the fact that the Nazgûl were the only ones to fall corrupt.) (Edit: Oh and also in Saruman's betrayal)
Of course my TL;DR answer would be that once you've turned your back on your creator, and your big brother Morgoth is gone, and dissolved your soul into a material possession, what is left to turn invisible. :D
Invisibility for hobbits was caused by their natural stealth features. the Ring amplified that tendency, like all others (greed in Dwarves etc..).
In other words, the One Ring wasn't an "Invisibility Ring", it merely aided those predisposed to it to become invisible.
Also the power of the ring was relative to the power of the bearer and/or the distance from Sauron. If you recall, the ring does something completely different when Samwise puts it on in Mordor.
Also, the ring was a completely different temptation to Gandalf and Galadriel because it would increase their overall power, not just turn them invisible. Bilbo and Frodo were mere hobbits. Thus it only granted them invisibility. I am willing to bet it granted Isildur powers beyond invisibility, thus why he prized it so. It doesn't go into detail as to what he gained from the ring.
Sauron is a Maia and he belongs into the Spirit World, as well as Valar and the Eldar partly and he can take several forms as an act of his own free will (giant wolf, bat, serpent, etc.). After the destruction of Númenor he could never take any form other than his terrifying one. So he choses to become visible and reveal himself to others.
My opinion is when crafting the One Ring, Sauron put into it the ability to pass into Spirit World. It's not the same as being invisible because the bearer of the Ring could actually be seen in daylight as a mere shadow, when Sun is at its peak. So lesser beings like Hobbits or Men could use the powers of the Ring only to extent of their own capabilities and eventually became consumed by it passing permanently into Shadow.
The One Ring is a product of Sauron's making, so it's evil and corrupted and has greater influence on someone who has a lust for power and domination like Black Númenóreans who became the Nazgûl. Sauron is already the embodiment of evil so the Ring has no effect on him, only extends his powers. He cannot turn invisible because he is in control of its powers unlike the others, except maybe the strongest among the Eldar not including Galadriel and Elrond if they wore the Ring, but they are all long dead.
All of The Valar had the ability to become invisible. In The Silmarillion, Morgoth / Melkor lost this ability due to investing too much of himself into Middle-earth. Sauron was a great shape shifter before he poured most of his native strength into the Ring, therefore I think he has the ability to choose whether or not he's invisible whilst wearing it.
Sauron and Tom Bombadil could actually use the ring. Invisibility is the power that is granted to those who can't unlock it's full potential.
Sauron actually IS the dark power that rules the Rings. As their Ruler, and as the being who created the Ruling Ring, and who made it to be subservient to his will, he himself is not subject to it.
The Ring obeys him, just as all the lesser rings obey it.
The title of the book answers this question: Sauron is literally "the lord of the rings". It is Sauron who is their lord and master. They obey him, not the other way round.
Sauron didn't become invisible because he was never visible in "this" dimension. The ring has one main power and purpose: connecting both dimensions. It existed in both dimensions. Once you wear it you access the other one. Thus Sauron needing it to come to "ours".
The One Ring turns everyone but Sauron invisible due to the fact that as the ring is part of Sauron and thus shares his "will". That will is so powerful and consuming that it covers you from sight.
In truth, it doesn't actually turn them invisible - it actually pushes you through the folds of the world partially into the wraith realm because there is no room for you. More on the will of Sauron can be found in The Silmarillion as well as other references throughout the short stories of J.R.R. Tolkien.
Well, Sauron doesn't have a body by the time of the war of the ring, so there's nothing to make invisible - his body was destroyed when Eru sank Númenor. Like other answers suggest, what people see when they look at him is a construct of his spiritual presence/power - as well as some armor and other such earthly objects.
