Nothing happens without a reason.
That was what Emiya Shirou believed.
Not every action or event necessarily had a justified purpose, but all occurrences had their underlying causes.
Slipping on a banana peel on the road was because someone carelessly tossed it aside.
An ant crushed beneath a careless foot was because it unknowingly ventured onto a well-trodden path.
If someone strolling casually through the street suddenly lost their head to a thrown axe, perhaps a noble had grown bored, or maybe someone's fingers had simply itched to toss something dangerous.
Even a simple sneeze had its triggers—whether physical reaction or subconscious thought.
There was always a cause behind an event, even if no clear reason justified it.
He wanted to understand—the hidden motives behind Esdeath's actions.
In truth, Shirou already had a suspicion. In a rotten, corrupt world such as this one, it wasn't particularly surprising for someone ruthless and bloodthirsty like her to appear.
He simply wished to confirm if he could somehow change her deep-seated views.
During this period, Esdeath had hunted food, providing Shirou with sustenance he needed to survive.
For this, Shirou was genuinely thankful.
Wanting to kill her and expressing gratitude weren't mutually exclusive.
Yet no matter what kindness Esdeath might show him personally, Shirou could never forgive the crimes she carried.
Only if she genuinely changed, lending her strength to those still living, would Shirou abandon his killing intent toward her.
If she refused to change, no amount of kindness from Esdeath would alter Shirou's resolve to end her life.
Even if a murderer later performed countless good deeds, that would never erase the truth that they deserved hell.
No compensation could ever replace a lost life.
But precisely because of this—should a criminal give up seeking redemption?
Would killing or tormenting them bring back those who'd died?
Clearly impossible. At least in Shirou's mind, those still alive mattered far more than the dead.
Instead of executing sinners outright, wouldn't it be better if they contributed positively to society?
Shirou held no right to forgive criminals on behalf of their victims, nor did he claim authority to exact his personal justice outside the rules.
These were simply his own selfish ideals.
If Esdeath truly reformed, and someone later came seeking vengeance against her, Shirou wouldn't intervene.
A life for a life, debt repaid—these truths were fundamental. Shirou had no authority to interfere.
Such matters weren't within Shirou's duty. He wasn't an avenger, merely someone whose actions occasionally aligned with others' quest for justice.
But if someone's revenge required sacrificing even more innocents, only then would Shirou step in to stop them.
"I was born in the Northern frontier region—"
Esdeath spoke openly. After all, the island held no one but the two of them. Instead of sitting quietly, why not exchange stories?
She began recounting her past without reservation—it wasn't something she kept hidden.
She was the daughter of the chief of the Partas Clan, a tribe specialized in hunting Danger Beasts. From a young age, the principle of survival of the fittest had been deeply ingrained into her mind.
Once, returning alone from a hunting trip, she discovered that the entire clan had been wiped out by the Northern Tribes.
Yet, surprisingly, she felt no hatred toward them; rather, it had only reinforced her belief in the strong dominating the weak.
Did she truly feel no hatred toward the Northern Tribes? Shirou wondered inwardly.
Now he fully understood why Esdeath later annihilated those tribes without mercy. Such viciousness didn't arise purely from upbringing; hatred was undeniably a factor.
Perhaps Esdeath outwardly showed no nostalgia toward her father or her clan, but the scale of her brutality revealed lingering sentiments buried deep within.
Shirou understood Esdeath's motives, yet he couldn't see her actions as justified. Fighting evil with greater evil was fundamentally flawed.
But Shirou wouldn't lecture Esdeath that slaughtering innocent civilians among the Northern Tribes was wrong.
After one's entire family had been slaughtered, trying to persuade that person to lay down their blade felt impossible. Shirou himself couldn't do such a thing; he believed in actions, not empty words.
"Survival of the fittest… It perfectly suits the current state of the Empire."
Shirou sighed softly. He wasn't from this world, and he knew he couldn't impose his own moral standards to judge their way of life.
While nobles feasted extravagantly, commoners could barely find grass to chew on. In an Empire corrupted to its core, Shirou wouldn't even find cannibalism shocking.
These people weren't merely struggling—they'd been reduced to livestock, kept alive solely by the nobles' whims.
Why didn't they rise up? Not because they failed to recognize their plight, but because they lacked the strength and blades to fight back.
Esdeath alone sufficed to suppress the entire Empire's populace, choking any hope of resistance.
This was true survival of the fittest—absolute suppression through overwhelming power.
Precisely because the Empire wielded such immense power, it endured, no matter how rotten within.
"But isn't there far more to life than just survival of the fittest? Even in your tribe, I imagine that at the very end, they tried their best to save the weakest among them first."
Just as Shirou wished to change Esdeath's perspective, she too wanted to alter his beliefs.
After all, Shirou was a youth who'd defeated her in an exceptionally short time. Anyone would desire such strength at their side.
"Yes," Esdeath conceded softly.
She couldn't deny it. In her memories, there indeed had been groups from her tribe fleeing desperately, carrying children and elderly with them, only to be mercilessly slaughtered when the Northern Tribes caught up.
These were people who'd lost their strength—or hadn't yet found it.
Undeniably, they were weak.
"Nobody is strong from birth. Everyone begins as weak. Didn't even you survive your childhood in those harsh frozen lands because your father protected you?"
Shirou vividly remembered his own first encounter with a demon—how utterly fragile he had felt. Just one casual strike from it could have pierced straight through his chest.