"I'm sorry."

Why was he apologizing?

Please live on without me. I'm sorry.

Because Maedhros always apologized before leaving him to bear the weight of the world alone? No—not the world. Their sins. Their sins transcended worlds—were heavier than a thousand vast lands of dense, unforgiving ice.

"Don't apologize."

At this point, apologizing was quite useless. Maglor bowed his head and smiled against Maedhros' neck, feeling his eyelids drop lower, feeling his gaze swim with black fish, ready to suffocate his vision. "Yes, brother." He sounded subdued, quiet, even to himself, and felt Maedhros' arms tighten around him.

They were quiet, for a long time. Seconds went by as months, and a month, now that Maglor looked back on it, seemed only like a second.

"Just close your eyes."

Maglor felt surprise bubble within him.

"Maedhros…" He looked up, but through the fog, the black fish that swarmed in the ponds, he could barely make out the face of his brother.

"I understand, Maglor."

His eyelids were getting heavier.

"Thank you."

The last drop of blood…

…is mine.

To make this clear—since clarifying it in the story kind of takes away from Maglor's instability and desperation—they are in a different life. This isn't in context with the Silmarillion. As mentioned in the summary, it's an alternate-universe story, where Maglor and Maedhros are in another world, and they have been tortured, beaten, and thoroughly defeated by their enemies. This is Maglor's musing as they wait to die. Each time they are about to die, their memories start flooding back, and of course, Maglor is the first person who realizes this and tries to approach the subject. As hinted in the story, also, this has happened more than once.

Poor Maglor!

I hope you enjoyed reading it!