He spoke in a monotone voice, both free from doubt or urgency and devoid of any inflection. He had been presenting himself as a cheerful man prior, but he now resembled a cold blade. She tried to grasp the mental state that led him to this conclusion, but it was in vain. There was nothing. Nothing at all.
"Your wife, right? Her?" Lemina stammered.
"Yeah."
"You kept talking about how precious she is to you. Weren't you calling her your revered princess and the like?"
"Aslaug is my most revered princess. She is everything to me. What of it?"
Lemina floundered. "Um..."
"What's the matter, Boss? Don't you want to win?" Berserker challenged.
"!"
A sudden realisation struck her. Right, this is Ragnar Lodbrok. A warrior from a world where survival hinged on killing others.
She thought she had understood on an intellectual level, but the reality was far harsher. Despite her training and ingrained calmness in the face of violence and death, Lemina now understood the vast gulf between her and a true Viking, a literal embodiment of war and death. He wouldn't hesitate to use even his beloved wife as a weapon. And he did so without a flicker of a doubt.

Fate/Lost Einherjar, Chapter 3