Eragon's face was smeared with blood. His sword, the mighty Brisingir, was splattered with gory guts while he was bleeding from at least 3 wounds on his body. He beheaded enemy after enemy, parts of his opponents rolling down into the matted long grass floor. He was an unstoppable force of nature, fighting enemies as if it was all he had done in his life. He killed his last enemy with one quick stroke of purple of his sword. He then raised his head.
"I challenge you, King Galbatorix!" He sneered. "You will pay. You will pay for Oromis. You will pay for Glaedr. You will pay for Brom. You will pay for anyone I, or anyone else, has ever lost. And most of all, you will pay for Saphira." As Arya knew, For Saphira had become a regular battle cry for Eragon, ever since she had died. And since then, all he ever focused on was her and avenging Saphira.
"Or are you too cowardly?" Eragon bellowed. He raised his sword, preparing for the moment Galbatorix would finally come out. He raised his pointed elfish ears to listen and squinted his hazel eyes. Then he saw Galbatorix, sitting on a throne of black ebony appearing to have engraved skulls and bones of the dead. It was a throne of pure evil, fearful energy surrounding it. Carrying this throne out to Eragon were little creatures he had never seen before; they seemed to be a mix of Urgals and Razzac.
Arya snorted in laughter, though there was absolutely nothing funny about the situation. Wow. Did Galbatorix think so little of them, consider them so beneath him, that he could not bother to walk to fight him, but had to be carried on his throne? She did not know whether to laugh or cry. She watched Eragon out of the corner of her eye, seeing him ball his fists and clench his jaw. Tears stung his eyes, but he quickly blinked them back.
"My, my…" Galbatorix said in his magnified voice. "All my favorite little heroes!" He chuckled, as if life was some big joke, which, well, it was. He waved his fingers in a casual way. "Are you here to pledge your allegiances?" In the middle of this sentence, he already began to attack all their minds with the Eldunari of the dragons, causing them to bow down in pain. More people of the Varden and spellcasters came to help, but as soon as they came in range of seeing Galbatorix, they were taken over.
"It- hurts-" Eragon gasped. He didn't even bother fighting any more and just curled up into a ball while Galbatorix took over his mind.
"You see," Galbatorix smirked, "We have more hidden Eldunari than you ever anticipated." He then spoke Eragon's true name, causing a shiver to run through his body. "Come here, Eragon…" He said in the Ancient Language. Eragon obeyed and stood aside the black throne.
"Well, that was easy!" Galbatorix laughed again while Arya stared, helpless. "Arya, little elven princess. Mind over love, duty over all, remember?" Arya felt fear run through her body, more fear than even when she was tortured. That was a quote her father had always said to her. How did Galbatorix know it?
"You have a choice, my young elven princess…" Galbatorix talked in the ancient language once again. "Me or Eragon? If you pick me, I will kill Eragon, then kill myself. If I go down, he goes down with me." Galbatorix used his bony, slender, pale finger to draw an X over Eragon's heart. "I swear it, and the world will be rid of me forever. Or… you pick to save your knight in shining armor, and he'll live… So shall you. And so shall I. And you will serve me forever, be able to stay together forever, and live. Don't forget, but then, I'll still be alive too!"
Arya closed her eyes, wishing she could not be here, now. She wished she was lying in the sun with Eragon, or swordfighting, or simply talking; anything, anything, anything. This decision was the worst torture Galbatorix could give her.
She raised her trembling hand. "Mind over love, duty over all…" She whispered over and over again. Her father's favorite quote, the one person he couldn't disappoint. It was obvious Galbatorix thought she would pick for Eragon to live, and she couldn't let him win.
She made a finger with her right hand and pointed at Eragon. Then, regaining her courage, she made a clear distinct X. Death to them both.

Well you only need the light when it's burning low
Only miss the sun when it starts to snow
Only know you love her when you let her go

Galbatorix's eyes widened. He had said he would kill Eragon and himself if Arya said so in the Ancient Language, and, with the Ancient Language, there were no outs.

Staring at the ceiling in the dark
Same old empty feeling in your heart
'Cause love comes slow and it goes so fast

Galbatorix stabbed Eragon in the heart. He appeared to choke, then collapsed on the floor. He was a fighter, though, and still wasn't dead. Arya could still faintly hear his last words.

Well you see her when you fall asleep
But never to touch and never to keep
'Cause you loved her too much and you dive too deep

His last words. "Arya- why-" He coughed out. Arya swallowed back tears. Only the weak cried. She then heard one last word: Saphira.

Well you only need the light when it's burning low
Only miss the sun when it starts to snow
Only know you love her when you let her go

Galbatorix took Brisingr, and without hesitation, stabbed himself in the heart. Arya tried to feel satisfaction at his death, but she couldn't. The price for his death was too great.

Only know you love her when you let her go
And you let her go...