In the Light Screen footage, while Welt and Siegfried were forming a temporary alliance, Theresa and the Valkyrie squad she led encountered Sirin elsewhere—and came under her attack.
When she encountered Theresa, Sirin used some means that would be troublesome to explain. In short, it was one of those "Honkai energy can do anything" methods that let Theresa see her past.
After seeing the horrific treatment Sirin had suffered, Theresa could not help but feel heartache and sympathy for her. She also wanted to save the poor girl.
However, Sirin did not appreciate it. Theresa was one of Destiny's people, and Sirin, filled with hatred for Destiny, only wanted to smash everything related to Destiny. With that level of hatred and obsession, if this were a magnetic-field madman world, Sirin would be at least a five-hundred-thousand-horsepower magnetic-field madman.
Thus, the exchange between the two was far from pleasant, and in the end, Theresa had no choice but to fight Sirin.
Without question, compared to the future principal Theresa, the current Theresa—still an S-rank Valkyrie active on the front lines—was stronger. Against Sirin, who was still a novice and poor at wielding her own authority, Theresa held a massive advantage. Relying on the versatility of the Oath of Judah, she completely suppressed Sirin from the very start, forcing her to dodge everywhere and making her afraid to confront Theresa head-on.
However, Theresa ultimately still lost.
She lost because she did not understand Sirin's abilities, and her body was pierced by a Subspace Lance created through the Herrscher of the Void's authority.
The Subspace Lance was no secret in the future, but at this point, when Sirin had only just awakened, it was an attack method that had never appeared before.
Moreover, Sirin had not created the Subspace Lance directly. Instead, she