- Chapter 3: To Your Gallant Visage at the Underworld's Edge
Theo succumbed to the feelings he had been holding back against Lena after the battle in which they lost Kaie. He berated her without restraint, seeing her as no more than their other oppressors, simply playing the saint to satisfy herself. He was calmed down by Raiden and came to regret the way he voiced his anger, despite not regretting anything he said. He realized that by taking out his anger on another, he had done the same as the white pigs that had made the Eighty-Six scapegoats in the first place, thus sullying Kaie's honor and death. He took the time between their next resonance with Lena to reflect upon his feelings, as well as if the Fox Commander he held in high regard would approve of his previous actions. In the end, though he refuses to apologize, he found it in himself to at least reset his view of Lena; he was the first member of the squadron to personally give their full name to her.
- Chapter 2: Panzer Lied
Theo was carried to eastward by Shourei with the rest of the 1028th Trial Unit and subsequently rescued by the Federacy's forces. After a month of quarantine, he was adopted by Ernst Zimmerman and lived as a civilian just like the rest of his squadron.
- Chapter 3: Wild Blue Yonder
Theo eventually decided that it was time to return to the battlefield after resting for so long. Along with the others, they managed to convince Ernst to let them enlist in the military. They eventually made him agree, with a few caveats. As per Ernst's conditions, he was sent to receive officer's training before joining the military, assigned to the 1028th Trial Unit's Nordlicht Squadron. Theo was separated from his comrades for a time, as they were split into different platoons.