The One

(Ost-in-Edhil, around year 1550 of Second Age)
The Lord of Eregion entered the smithy... No, to be more exact, a Noldo entered the smithy - the titles and duties should stay outside the temple of knowledge. Remember just one.
You are Firstborn, and you are the first one to know. You are vis-a-vis with the Universe. No matter that you are just one of many in general - you must find your frontier where no one had set foot before. You are Noldo.
Celebrimbor smiled when he recollected the words of the Great Feanaro which he heard not once in his childhood. Those times seemed no more than a myth now. Valinor unmarred, Grandfather alive and in the peak of his glory, his laboratory keeping constantly the metal, tepid smell of experiments and discoveries. Celebrimbor hoped that his smithy smelt the same, without Beleriand admixtures of broken grass, blood and fear.
Father did continue metalwork in the Middle Earth. But it did not feel the same. True masterpieces left Curufin's anvil - spearheads, and arrowheads, and daggers, and swords, and armour, and shields, and more swords - one- or two-sided, one- or two-handed, straight or curved, with chutes for blood flow... When Curufin was taking hammer he saw not the Ea, but his foes. Morgoth, Orcs, Balrogs, Arfings and Nolfings, Mortals... He would squint his eyes viciously, and fire gleamed red in his eyes like the blood that would run down those blades.

It scared Celebrimbor more than desperately vast forces of Morgoth and the Prophecy of Mandos. He didn't know how to prove to his father what's wrong. He didn't know where the border lies between a heroic legend and fire of madness. And Noldor hate ignorance.
"In that time Celebrimbor the son of Curufin repudiated the deeds of his father and remained in Nargothrond".

He wouldn't repeat that mistake. He left his past in the past, he chased the memory-feeling from the memory-knowledge, everything he left: Nirnaeth Arnoediad, Dagor Bragollach, two kinslayings at Alqualonde and the Mouth of Sirion.
Was it difficult? Not quite. Celebrimbor held one picture in the treasuries of his memory, that could outshine all other remembrances.
...Beleriand was breaking apart and crushing down into the turbulent waves behind the Noldor. And in front of them... a new wide world, of which Feanaro spoke on Tuna, was opening. What was promised under the torches came into reality in the glorious daylight. And Celebrimbor believed in the Oath again. But now instead of "Silmarili" he was whispering "Endore" deep in his heart. Valar were withdrawing from the world and taking the Dark One with them. Endless space was falling into the hands of newcomers like a ripe apple. In decades he had a piece of land, and went freely to sea (with allied Falathrim), into Eastern woods (with allied Silvans), to the roots of earth (with allied Dwarves). Why conquer the whole Arda when he could see it or get any rare ingredient for experiments through friendly nations? Like this coal from Dale. Celebrimber added one more scoop onto the furnace. The coal crackled and shot a spark. The Noldo hissed and brushed his burnt cheek.

And then Annatar appeared. The fair appearance of that (undoubtedly) maia gave Celebrimbor creeps, but he kept his countenance reserved and welcoming. Knowledge has no colour or side, he was taught, and a knowledge from a maia could be priceless. Moreover that the ideas of the mysterious benefactor seemed nice at first. Then a thought hit the Noldo: why should Valar send an envoy to make Middlearth more beautiful than Valinor itself?
Celebrimbor began to collect rumours and sought society of Annatar more often. Galadriel and Elrond protested, but the Feanoring disregarded them? and the departed in a huff and indignance. And he noticed that most of time maia was facing South-East or East. So what do we have there? Avari of Erin Lasgalen reported of Orcs. Numenorians settled at Anduin were telling about orcs and wild men with black gonfalons.

Celebrimbor poured a measure of Harad gold sand into a crucible and placed it on the furnace.

Moreover, Annatar's speeches of Valinor reminded many Eldar and Sindar of the Blessed Lands, and their hearts were turning back to the West. That way the stubborn Lord would stay alone at this side of the Great Sea one day. They needed a positive example, Celebrimbor thought in exasperation, so that they believed again in their own powers, once and for all, and forgot about the way back. Unmasking and defeating a dark maia sounded positive enough. Especially if he coped alone. Returning the Middle Earth to Qendi... He found his frontier.

So... He smirked, though rather hysterically. A maia is less than the Dark Vala himself, but will suffice to overthrow elven forces. Only one half-maia has succeeded in defeating Sauron previously. "We'll try another way", Celebrimbor thought slyly. "Creative one".

He took the crucible with molten metal out of the furnace. The mould was ready long ago - a plate with round chute the size of a nail. He poured a drop of the glowing liquid carefully inside - and a ring was ready. The next trick would be to extract the ring after it remembered its form but before it hardened - he had yet to encrust it with a small charmed stone... Not a great charm, just a bit of health enhancing.
Quite a nice little ring of power. Must be given to some human - Mortals can't handle great amounts of energy anyway.

He would have never guessed how hard it is to concoct a proper phrase - not easier than to forge and temper a mithril spring. How difficult it was to drop that phrase occasionally. Luckily, Annatar was seeking society of Noldor chiefs too. Long night conversations had become usual thing, Celebrimbor started bringing old wine... The peak of actressy was to fake incoherent speech flow when he was actually almost drunk. The play seemed successful, as after a long talk of circles, and rings and axles and the world structure the maia left the guestroom of Gwaith-i-Mirdain palace verrry thoughtful.

around 1600 of II Age

In Mordor, in the Rifts of Doom on Orodruin, Sauron was forging the Ring of Power. Those fools of Noldor were waning through pride, drinking and idleness. They won't even recognise a really great, genius idea in their intoxicated twaddle. He was Maia, he could smash any of them with a thought. But not all of them together. And orcs were just sword fodder. If he could increase his power... and he could!
A ring form was coming to existence amidst the hellish flame.
Power of maia circled in it, caught its own trail, interfered with itself and duplicated, multiplied itself immensely... The One Ring was ready. It watched its creator from his hand and gleamed with power hidden inside.
But... the power was all within the Ring, not inside him, as before. He felt.. hollow. He put it on his finger in haste. The power flowed around him, obeyed his every thought but still it felt detached. Sauron froze. A new fear shadowed his being, the fear known maybe to Eruhini - to be parted from the material constituent.
He tried to draw his power back but the turmoil whirled past his mental grip, and the ring had neither end or beginning which he could pull at. It could twist everything around it but was unable to change itself. His Power protected him before. Now it was protecting the Ring. Gorthaur felt betrayed.
The Ring gave him great power but made him vulnerable. An elven spy with a knife could.
"Celebrimbor! You bastard!!!" Sauron roared.

After some screaming and bashing around Thu calmed down. "Celebrimbor is a Noldo", he thought, "and moreover, a Feanoring. He wouldn't share his plots with anyone. He alone knows what he did to me. No elf - no problem". He sneered and went out to give orders.

notes

Arfings - the House of Finarfin (Arafinve in Qenya)
Nolfings - the House of Fingolfin (Nolofinve in Qenya)
The rest of names can be easily found in Silmarillion.