One thing this trip has undeniably been good for is Celebrimbor's athleticness. She keeps pace.

Aredhel wouldn't have allowed anything else. 

There's a threshold near the crater at the top. An opening in the side, one of the few which does not belch smoke nor flame - 

They make it past the threshold a scant hair before the world outside it erupts in blinding light and power and flame - 

But the hall it seems is shielded, and while the air is so thick with power they can hardly breathe, and while the entire place shakes like a ship dashed upon stormy rocks - it holds, at least in terms of structural integrity and not being actively on fire or full of lava. 

This might be... worse than anticipated.

"Since fucking when was Sauron this strong???" 

"Never, that I saw. Unless she concealed more of the rings' potential than I thought."

"That would violate everything we learned about the Ainur, and even about the nature of the world..."

"What do you think the goal of all our tinkering was, if not the violation of the natural order?"

"Well, she's putting it to good use now."

"Then let's go cut off her hands."

Further in - Aredhel will keep her bow strung and knocked, her long dagger in easy reach at her waist, a hum in the back of her throat. 

Her previous sentence notwithstanding, Celebrimbor herself is ready to slit a throat.

They don't find Sauron. 

They do find a rift in the air, a mass of fire, a contained explosion in eternal motion. And they do find that sense of power continuing to build, though it's - different. It isn't the choking oppressive smog of the world outside, but a common power, a hum growing around all of them - a Song any can grab and twist to their own ends if they dare raise their voice loud enough. 

This is not how Sauron wields her Power; the world outside - its heaviness, its barren pettiness and cruelty, its hoarding of all power for itself, the boot it pressed on the back of any who entered - those were fully typical of the Sauron they fought in the first age. She shares only as a trap, a hollow lie - she doesn't bestow boons on her enemy for their defiance, nor does she walk so plainly and unguarded.

This is not Sauron.

This is worse. 

Yeah. Worse is one word for it.

The fire flares out in a blinding spiral -

- Which resolves into a horrifyingly familiar shape. A woman, perhaps a hair shorter than Celebrimbor; her skin like a flame given flesh; her eyes like lava, now warmer and glowing, now darker and cooling; her hair like the untamed void before the Song began, the limitless potential of all existence; her raiment like the wild laughing earth beneath their feet, like an explosion, like a birth of new worlds.

"Not quite the welcome I expected on my return to this world," Melkor says, and her laugh is the most awful and awesome of everything she is - her very voice is Song, and her laughter echoes with all the wild fury bound in the forges of the earth. "I truly expected trumpets, whether triumphant or challenging. But this is much more my taste."

"What, the empty husk of a traitor's workshop?"

"Is that where this is? But, no. I meant the faces of those welcoming me."

"We are not here for you, Morgoth."

"A pity. Both of you have ever been the sort of person I admire. Whatever are you here for, then?"

"Don't you have a sun to blot out or something? Why would you care?"

"The Sun seems no longer run by a Maia; I have no objection to that. And I care because I am curious about one who can stand before me without flinching."

"What use would flinching be? I came here to kill a Maia."

"Oh? Which one?"

"Sauron." The venom in Celebrimbor's voice condenses a slightly acidic mist out of the lingering power of Melkor's arrival.

"Oh, what has she done now?" Melkor speaks with the approximate tone of someone whose beloved dog has a rather terrible habit of chewing on the furniture.