Note: events are not necessarily presented in chronological order.
Soren and Maggie find Haru, and brand him with a demonic brand that will keep him from being subjected to any magic without severely injuring or killing him. This is only a temporary measure, but it will keep them from using magical interrogation techniques on him.
Soren is inducted into the Holy Brotherhood officially, meeting with some of Maggie's former associates, Holy Brothers Maus and Ratte.
The Headmaster stumbles upon Kiyo in Soren's dorm room. As a "punishment," she is promoted to a higher class due to her magical skill and improved performance, keeping her away from Soren. He feels guilty for being relieved, since that will make it easier to sneak around as a Holy Brother. She nearly has a nervous breakdown, but they're allowed to keep dating. Just no more sneaking off for hanky panky.
Kiyo and Soren help the Headmaster develop a revised version of the Peace Bond for the next War Game, which will be part of what marks them as ready for their second year at the school. Soren becomes aware of magical batteries used to power some of the schools' fabricata.
Rose continues to have issues with her magical control, but Soren comes up with a solution to an energy problem the Headmster has, and Rose's problems in one fell swoop. They realize that if she charges the batteries, her "excess" magic is bled off, and she's able to keep under control.
Mariko and Paul's relationship continues, but Soren realizes that Paul is just out to score with Mariko, when she thinks she might have found The One. He keeps this quiet, since he doesn't see an issue with it, from a demonic perspective. Paul mentions some things that make him think that he might be a good recruit for the Holy Brotherhood.
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Soren also meets Rei Yamaguchi, a girl in his class with out of control magnetic powers who sounds like another Holy Brother in the offing. Thinking of Haru's sad state, he doesn't mention her as a possible recruit to Maggie. It's bad enough that he's stuck.
Finally, the Holy Brother doctors are the military hospital aren't able to keep claiming that Haru is too ill for interrogation. The only option is to kill him. Maggie leaves the job to Soren while she draws away attention, which he suspects is a test for him, and because she couldn't bear to do it herself. The plan is to have Soren go in with the Nurse Kazushi disguise and poison Haru under the guise of giving him his daily medicine.
He blinks. Seeing Haru in that vulnerable position, he can't stand to assassinate him, since he has only ever killed people in a fair-ish fight. Plus, poisoning him makes him think of his mother's death. When Soren drops his Nurse Kazushi disguise, Haru flips out and tries to kill him with his insect control powers. Soren tries to talk him down, but then Haru starts screaming that Soren is a demonkin at the top of his lungs, and Soren puts him down.
Maggie demands to know what that was about, and he realizes that she wasn't grateful for his attempted mercy to Haru. She had already written him off.
On his way back from the mission, after he and Maggie have split up to avoid being seen together, he stumbles on Paul and Mariko about to make love in the woods. Soren, feeling low, decides to break the news to Mariko, much to Paul's consternation. They break up, and he wonders why he even bothered to do that.
He concludes that he's taken steps he can't take back, and that he needs to get out of Japan before human softness completely overwhelms him. And, Maggie's Holy Brothers are his best way to do so.