Roswaal
—To resurrect his teacher, Echidna.
This obsession was what sustained the man named Roswaal.
He didn't know why he so desperately wanted to resurrect his teacher.
He didn't even know why it had to be done.
Roswaal remembered that his teacher had saved him, remembered that she had taught him, remembered that his childhood had been filled with happiness because of her.
He remembered being defeated by the Demon of Hesitation, remembered his teacher being killed by the Witch of Envy, and even remembered that he liked his teacher very much—not the kind of affection between teacher and student, but the kind between a man and a woman.
Yet, Roswaal couldn't remember why this obsession with resurrecting her was so intense.
Still, Roswaal didn't find his actions strange, because he was merely human.
Yes, Roswaal was just a pure-blooded human.
Four hundred years was simply too long a time for any human.
Even though he had, using his outstanding talent and his teacher's research materials, successfully used magic to transfer—or rather, possess—the bodies of his own descendants, memory loss was still inevitable.
So Roswaal simply believed that he had forgotten some important reason.
After all, there was even one reincarnation where he ended up falling in love with a man.
Even now, he still admired that man's way of life.
—No, something feels wrong.
Was it really just because he loved %*#¥@?
Roswaal held his head.
He felt as though some strange thought had just crossed his mind, but no matter how hard he tried, he couldn't recall it.
Still, Roswaal didn't dwell on it for long.
People experience flashes of insight all the time in life.
He took out his Tome of Wisdom, and began reviewing his actions over the past few days.
Just thinking back to the contract he made with the boy named Subaru three days ago made Roswaal smile.
Even four hundred years of self-cultivation couldn't suppress the immense joy that surged from within him, because that boy was his trump card for resurrecting his teacher—the boy who possessed the ability to return by death.
To ensure that this opportunity would be flawless, Roswaal had been acting according to the guidance of the Tome of Wisdom ever since that day.
Upon returning to the royal capital, he contacted the so-called "Mother" of an assassination organization through the hidden Bowel Hunter in the capital.
Using her hatred for the Sword Saint, a large sum of money, and the intelligence he possessed, Roswaal successfully gained the full support of the assassination group.
On the third day, Roswaal first persuaded Ram and Rem to infiltrate the Astrea territory.
He then himself snuck into the southern Empire—though calling it "sneaking in" might be misleading, since Roswaal was, after all, the strongest guardian of the border.
His presence couldn't be easily questioned.
Using his information network, Roswaal quickly located the strongest man in the Empire—First General Cecilus. Roswaal was rather fortunate that Cecilus hadn't wandered off, because if he had, Roswaal, who couldn't just fly around the Empire at will, might not have been able to meet him.
Though he was nearly killed, Roswaal followed the instructions from the book, offered a famed sword he had found, and managed to win the favor of the collector-general, gaining a chance to speak.
Then, using the words of the "Purger King" provided by the Tome of Wisdom, he persuaded Cecilus to assist in fighting the Sword Saint, Reinhard.
On the fourth day, after returning to his mansion, Roswaal found a way to persuade the Beast of the End.
Though this beast had the ability to sense malice, unfortunately, it was rather dumb.
It had a number of quirks: overly emotional, overly protective of its daughter, and fond of acting on its own.
While it seemed like an unshakable support for Emilia, in truth it was extremely fragile—like the so-called Maginot Line.
After successfully dragging Emilia into the whirlpool of the royal selection, Roswaal easily secured the beast's cooperation.
Everything should have gone smoothly, just like the book foretold—until yesterday.
After finally assembling enough fighting power, Roswaal once again infiltrated the Astrea territory.
That was when he felt two monstrous powers clashing.
As he got a little closer, Roswaal realized it was the aftermath of a battle between Ram and Reinhard.
At first, Roswaal was confused.
Ram had the Clairvoyant Eye, and theoretically should not have been found.
Then came a flicker of panic—this could mean the Tome of Wisdom had made a mistake.
For someone who treated the book's words as divine prophecy, that possibility was a devastating blow.
But ultimately, joy followed—as Roswaal began to understand what had caused the mistake in the book.
"Subaru... you really are incredible."
Roswaal didn't stay to watch the battle.
He quietly fled and hid in the forest, pulling out the Tome of Wisdom to reflect on his actions.
He gently caressed the black book in his arms as he sighed.
Having confirmed there were no flaws in his actions, and with the joy in his heart finally fading, Roswaal felt a different emotion: resentment.
He had already prepared to give up everything, but now that he realized he was the last sacrifice, and that the one to come after him would receive such a powerful "trump card," Roswaal finally felt a hint of unwillingness.
"Is this how you all felt too...?"
Roswaal spoke to those who no longer existed.
The conversation lasted into the night.
"Yes... after all, you were all me."
Roswaal nodded affirmatively.
"Mmmm!!"
He let out another long sigh.
As a demon who had spent 400 years invading the bodies of his own descendants to resurrect the teacher he loved, this little bit of resentment was nowhere near enough to shake his resolve.
He carefully returned the Tome of Wisdom to his chest and stood up.
At that moment, only determination shone in his eyes.
"The rest is up to you."
Roswaal spoke to the yet-to-exist victor, then walked out of the forest.
Capella, Cecilus, the Beast of the End... Roswaal went to each of them, explaining the plan for tomorrow.
Yes—tomorrow.
Although the Great Rabbit would only arrive the day after, having witnessed Subaru's strength, Roswaal decided to move ahead of schedule.
After all, although the Great Rabbit was one of the Three Great Demon Beasts, its power in this battle—the siege of Astrea, where a Sword Saint, Demon, Sin Archbishop, Oni God, and Imperial General all gathered—was not insignificant, but also far from being enough to change the course of war.
Thus, 36 hours earlier than Subaru remembered, the final battle for the Astrea territory began.