Eldest Daughter Sirin

[Now beginning answer analysis]

Eldest Daughter: Sirin

Sirin was one of Schicksal's test subjects in the Babylon Tower. During the experiments there, her friends and companions died one after another. The Schicksal researchers didn't even treat those dead girls as human beings—they discarded them like scrap.

Watching her companions die off one by one, when her last friend Bella perished, a despairing Sirin prayed to the gods for power, and the gods answered her prayer, granting her the Herrscher Core of the Void.

Thus, the Second Herrscher was born.

Later, with the help of the Honkai Consciousness, Sirin obtained the Honkai Energy sealed by the Previous Civilization on the moon and acquired four Herrscher Cores—Wind, Death, Flame, and Thunder—becoming a Five-Core Herrscher. She also learned a vast amount of knowledge left behind by the Previous Civilization.

Afterward, she used a meteorite to threaten the Second Herrscher of Reason into coming to the moon alone, defeated him, and took his Herrscher Core.

Returning to Earth, Sirin used her Herrscher Cores to turn her former companions' bodies into puppets and granted them the power of Pseudo Herrschers, but they were eventually defeated by Schicksal's Valkyries.

After that, Sirin obtained several Feathers of Dust and pulled Seigfried and Cecilia into an illusion.

Inside the illusion, the original Sirin intended to create a terrifying nightmare to torment them, but she accidentally crafted a peaceful, ordinary world.

Watching Seigfried's family live a simple yet happy life in the illusion, Sirin couldn't help but think, "If I had never encountered the Honkai, if my mother hadn't died, could I have had this kind of happiness too?"

She envied and resented them—envied the Kiana in the illusion, resented those who had stolen her own happiness. So she decided to destroy theirs.

But for some reason, Cecilia and Seigfried treated her as their own daughter. Feeling their love, Sirin couldn't bring herself to strike.

Later, sensing Bella's defeat and remembering that Seigfried had wounded her wings, Sirin decided to kill him, but Cecilia saved him.

Sirin realized Cecilia hadn't been hypnotized by the Feather of Dust and thought she had been deceiving her, so she resolved to kill them both. At the critical moment, Welt saved the couple, and Sirin dispelled the illusion.

Outside the illusion, Theresa restrained Sirin with the Oath of Judah and pierced her heart. But Sirin used the power of the Herrscher of Death to repair her heart and resumed fighting, engaging Seigfried.

After being defeated by Seigfried, Sirin triggered a Great Honkai, inflicting the residents of Siberia with Honkai Sickness.

Meanwhile, at Schicksal headquarters, Otto, terrified by the power Seigfried had unleashed, ordered the launch of a Honkai Fission Bomb, intending to kill both Seigfried and Sirin.

Though Cecilia used the Black Abyss White Flower and the Holy Blood of the Schattenia Family to save the people of Siberia, the effort left her severely weakened.

In Sirin's final moments, Cecilia embraced her, giving her one last warmth and saying those words:

"Ich liebe dich" (I love you).

And together, they perished in the explosion of the Honkai Fission Bomb.

[Theresa: So that's the truth of what happened back then?]

[Kiana: How is that possible? Mom was killed by her own people at Schicksal!]

Kiana's faith in Schicksal wavered in that moment. No one could have imagined that the strongest S-rank Valkyrie of her time, Cecilia, hadn't died fighting a Herrscher, but had been killed by her own comrades at Schicksal.

And all because of a ridiculous reason—that Seigfried's power was too great.

[Furina: That blond bastard wanted to kill him just because Seigfried was too strong? That's outrageous! If this were my world, I'd have him locked up in Meropide for life!]

[Yanqing: If someone like that existed on the Luofu, I'd personally throw him into the Prison of Imprisonment.]

[Tesla: If it weren't for that blond bastard's research, none of this would have happened!]

[Otto: Dr. Tesla, all of this was necessary to fight the Honkai.]

[Elysia: What a pity. In the illusion, you could see that Sirin no longer had any desire to destroy humanity. If Bella hadn't been defeated, she might have become another Herrscher fighting for humanity?]

Heaven knows how excited Elysia was to see the First Herrscher fighting for humanity—it meant her sacrifice hadn't been in vain.

Especially when she saw how happy Sirin looked in that illusion. At that moment, she even felt Sirin could have become a Herrscher who fought for humanity.

But in the end, both Sirin and Cecilia died under Schicksal's Honkai Fission Bomb.

(Thanks to "Eh? Eh!" for the tip. Posting another chapter today.)