I bid you welcome!
This is what I think Murtagh would be doing while in Galbatorix's clutches. There's no real plot, just exploration of character. I love Murtagh. I think he's the best character in the Inheritance series, because there's so much depth and-- and interestingness to him. Anyway, I hope you like it as much as I do.
Sir Gwydion
In the mist-bound tower of Urû'baen
Murtagh slammed his fists into the wall of his tower, his prison, his home. He strode over to the beautifully carved desk and swept its burden of inks, scrolls, pens, and parchment onto the floor with a crash. Growling, he paced across the about the room like a caged animal and snatched up a piece of the mirror he had already broken. He focused with all his strength on Eragon, and muttered, "Draumr kópa." The shard's reflective surface turned flat black. The shout that tore from his lips was unintelligible, save for its source: anguish and frustration.
Thorn hummed deep in his chest from where he sat on the tower's broad balcony. When he heard his dragon, Murtagh's savage expression was replaced by on of bitter tenderness. He joined Thorn, and leaned against the iridescent crimson of his scales. Together, they watched tendrils of mist twine about the dark city of Urû'baen.
"What do you suppose Eragon would do, if he and Saphira had been here?" Murtagh asked, calmer now. "We're brothers, after all. Equal chances, equal strength. But he would kill himself, rather then serve Galbatorix. Why? He loves Saphira, I know. He's curious about everything, and yet he'd give it all up, all the things he might learn and all his years with her, to save other people's lives. Its strange," he laughed bitterly. "But I was wrong. Brothers, yes, but equals, no. I never had a chance, not like he did. I was doomed before I was even born, doomed from the instant my father betrayed the Riders. Fated, condemned. And I was wrong, too, in saying we have equal strength. For all I could crush that tower with a word, just a single word in the ancient language, I'm weak, compared to him. He's free. He's not cursed with our father's deeds, or with Galbatorix. There will be no ill fate for him. Or if there is, I know that fate intimately. His name is Murtagh, and he lives here, a prisoner in this tower with us, a blight on the face of this world. And if we'd both been here, together? If Selena had never left Morzan's side, would he be my double? Would I even be the same, if I hadn't be brought up alone and hated by all around me? Is who you are born with you, or is it in how you grow up? Does it even matter, when there will always be a Galbatorix to rule, and a Varden to oppose him, and and Eragon to bring them hope. And, perhaps, a Murtagh, too, to kill his brother in the end. How can I kill him, who is my brother, the only friend I've ever had? But I will, I know. 'There is no redemption for the soul that slays his friend and not his foe.' Kind of Galbatorix, to give me things like that to read. But I will kill him, in the end. Is my fate, my wyrd. Even if I were like Eragon, I would have no choice. Were I to throw myself from this tower, I would still have no choice, because Galbatorix knows my name. Our names, I should say. And he will never let us go." Murtagh paused as he heard footsteps racing up the stairs to his tower. A fist hammered on the door.
"My lord Shur'tugal!" a voice called. "His majesty King Galbatorix bids you make ready to ride at dawn tomorrow, when we leave for Surda, and the defeat of the Varden." The footsteps retreated back down the stairs.
"Very well," Murtagh said harshly into the silence. "So let it be. So shall it be done. We shall fly to their destruction like the very shadow of death, shall we not?" His armor rang softly as he put it on piece by piece. "Or rather, the blood of our friends. The death-shadow shall only come of we fail. I'll tell Eragon, before the end. Tell him who his father is. Because after all, we aren't so very different. Aye, that we are, the opposite and the same. Mirror images, the edges of a single blade. And who is to say otherwise."
A sudden noise behind him mad him turn sharply, to see a scroll on the desk that had been empty. It bore the seal of Galbatorix, and the traces of his magic. Murtagh read the scroll in silence, then laughed, as bitterly as ever. " So, not to kill my brother after all, but to condemn him to my fate. Come, Thorn, let us fly to the death of all hope."
The young man mounted his dragon, and flew off into the dawn, which, to him, was darker then any night.