A Twist of Fate (Fate Zero & Fate Stay/Night:UBW)

Sonnet 18: Chapter 2

Two years after the wedding.
Eritrea pivoted her foot, steadying herself before lunging forward with her dual katanas. Diarmuid deftly moved aside to dodge the attack.

"You've become much faster now, amour." he remarked.
"All thanks to you, my love."

The clashing of weaponry continued, just another day in the lives of the married couple. Before Eritrea could deliver her surprise attack, she dropped the katana in her right hand and gripped her abdomen. Diarmuid immediately rushed to her side.

"Anata? What's wrong?"

The pain was excruciating, and she started to see flashes of Medea in between pitch black shadows.

"No... It can't be."

The katana in her left hand was still clenched furiously out of habit. Then her vision went dark and she dropped the blade. A horrible clang of the sword sounded as her eyes fluttered close.

Eritrea woke to the sensation of wet cloth on her forehead. Slowly opening her eyes, she saw a silhouette beside her. Dark hair, broad shoulders, a gentle but slightly perturbed smile.

"Feeling better?" the silhouette asked.
When her vision cleared she replied.
"A little."
Then the flashes came back.
"Ah!"

Pressing her palm to her forehead, Eritrea bolted upright as if waking from a bad dream. She clutched the sheets, anxiety in her widened eyes. Diarmuid dropped the cloth and held his wife, his own fear heightening.

"What happened? What did you see?"
"Come with me, there is something I must find."

In the century old library, Eritrea skimmed through books, flinging them aside when it wasn't what she was looking for, all the while muttering to herself.

Diarmuid's frown deepened. He had offered to help moments before but his words were unheard by Eritrea, too absorbed in her task and the dread in accomplishing it.

"Must be here, must find it. It must be somewhere-"

She spoke hurriedly to herself, tossing volume after volume behind her until she found a thick burgundy hardcover. A small smile cracked on Eritrea's face, triumph mixed with terror, for she had found what she wanted but its contents would only confirm her fears, elaborating the severity of her condition.

She hastily leafed through the book, nearly tearing the fragile paper. Her breath shook until she stopped at a specific page, eyes roaming across the text. Eritrea's lips parted and her knees buckled. Diarmuid swept in to catch her, waiting patiently for an explanation.

"It is as I feared."

Her finger guided him to a passage. Diarmuid felt a steel ball drop into the pit of his stomach.

"The last spell she attacked me with on the volcano during the second war was no ordinary spell. The physical wound, though healed swiftly, will inflict a side effect on its victim. Vivid nightmares of the one who cast the spell, dreams of what the victim fears."

Diarmuid's stern gaze was now fixed upon his wife.

"This condition... Usually leads to permanent deterioration of the brain and inevitable madness..."

One week later.
"It's nothing, my love. I've just got a lot of rescue mission reports to complete." smiled Eritrea. 

But Diarmuid learned to see through her lies a long time ago. She wasn't fooling him now.

"Amour, what is it? Please, tell me."

Realizing that pretense was futile against her husband, Eritrea decided to come clean with the truth.