My first attempt. Please don't be too mean. And I obviously don't own the characters.
This is post-story, so Fai is the dead twin and Yuui is "Fai"
~{[(o)]}~
Fai was a dreamseer.
Yuui was the warrior, ever fighting a losing battle. Fai was the healer and the seer.
The dreams began when he was three years old.
~{[(o)]}~
"NOOOO!"
Yuui bolted upright and turned to his twin. "Fai? What's wrong, nii-chan?"
Fai sobbed into his brother's shoulder, incoherently muttering. "Blo-blood…everywhere…al-all dead…"
"Fai?" This was too much for an innocent three-year-old to comprehend. "Blood? Is Fai hurt?"
Fai took a deep breath. Nothing could bring him to hurt his precious brother.
He smiled. "I'm fine. Nightmare-'s all. Go to sleep Yuui."
"'Kay, nii-chan."
It was the first time Fai had ever lied to his brother.
~{[(o)]}~
Fai didn't sleep again that night. Or the night after that, or the night after that. In fact, he never slept again until the terrible defeat of the entire Valerian army was publicly known.
He didn't want to wake his brother.
Fai was young, but his three-year-old's mind already knew that he would always protect his twin.
Because Yuui was the weaker one. Since birth, Yuui had reached Death's Door again and again as he was plagued with life-threatening illnesses. But Fai never so much caught a cold.
It wasn't fair. But who were the Unlucky Twins, to speak of fairness?
Yes, I promise. Fai vowed. No one will ever hurt my little brother.
~{[(o)]}~
When Fai was five, he learned that the futures he saw could be changed.
~{[(o)]}~
Yuui. Fai woke instantly, disoriented but thankfully silent. He had long mastered the art of waking from nightmares without disturbing anyone.
Then the dream came flooding back. Yuui. The shining knife. Mother's face, terrible in its hate. Blood everywhere-Yuui-no, he wasn't dead, he's perfectly fine, sleeping right next to-
And Fai gasped. Yuui's half of the bed was terribly, ominously empty.
"YUUI!" he screamed, and bolted out of the door.
No! he thought as he raced to his mother's room. No, Yuui's fine, he HAS to be fine.
That's when Fai heard the screams.
"Mother! Don't!"
A scene from his nightmares. Yuui's shirt, a bloody mess. His eyes, wide with fear. Mother's knife, pressed precariously against his throat-
The spell was out before he could stop it. A blinding beam of energy, icy blue like his eyes. And the knife was deflected…
Freya twitched in surprise, her hand moved to her breast involuntarily in fear as the knife seemed to burst into flames, and fate sealed itself.
And with a moan, the lady he once called mother fell in a heap, undeniably dead. By his own hand.
Matricide…no wonder they deem us unlucky. Fai thought wryly.
Fai fell back, and just before he fainted he thought: It wasn't supposed to be this way. But at least Yuui is safe.