The Fallen Angels never made it past Rias's defenses.
Dean watched from the back of the training ground as the crimson-haired devil moved with practiced efficiency, her power creating barriers that repelled the intruders without breaking a sweat. It was impressive, in a detached sort of way. But what fascinated Dean more was how she did it. The flow of energy, the structure of the spell, the way she layered her defenses.
He was already taking notes in his head.
After the Fallen Angels retreated, Rias turned to address her peerage. "They're getting bolder. We need to increase patrols around the school."
"On it," Yuuto said, his hand already on the hilt of his sword.
But Rias wasn't done. She turned to Dean, who was still standing quietly in the corner. "That's the reality of our world, Dean. Constant threats, constant vigilance. Are you still certain you want to be part of it?"
"More certain than ever," Dean replied. "I just watched you handle five Fallen Angels without breaking a sweat. Which means there's a system to all this. Rules, techniques, methods. I need to learn them."
Rias studied him for a long moment, then nodded. "Fair enough. Come with me. There's something I want to show you."
She led him deeper into the training ground, past the main chamber and into a vast library. The shelves stretched up three stories high, filled with books on magic, demonology, history, and techniques Dean couldn't even begin to categorize.
"This is the Gremory family archive," Rias explained. "Most of these books are about devil magic and sacred gear theory. But there are other sections." She gestured to a different wing of the library. "Those contain information about other paths to power. Witchcraft, shamanism, angel magic, even some human techniques that have survived into the modern era."
Dean's eyes widened. This was more than he'd hoped for. "Can I...?"
"Read whatever you want," Rias said. "But I'm going to give you a piece of advice, Dean. Don't just study theory. Theory without practice is useless. You need to find someone who can teach you, someone who actually practices unconventional magic."
"Do you know anyone like that?"
"Actually, yes," Rias said thoughtfully. "There's a witch who lives on the outskirts of town. She's not affiliated with any faction, which makes her valuable for someone like you. Her name is Grayfia... no, wait, that's not right." She frowned. "There's a human witch named Shizuka. She runs a small shop in the commercial district. She's not particularly powerful, but she's knowledgeable about older forms of magic. I can arrange an introduction if you'd like."
"I'd appreciate that," Dean said.
Over the next week, Dean spent every free moment in the library, devouring information. He read about the basics of magic theory, about how to sense and manipulate magical energy, about the different schools of magic that existed throughout history. Some of it was dense and difficult to understand, but he pushed through, driven by the knowledge that every page was bringing him closer to power.
Meanwhile, Issei noticed the change in his older brother. "You're obsessed," he said one evening as Dean sat at the kitchen table, surrounded by books he'd smuggled out of the Gremory archive.
"I'm focused," Dean corrected. "There's a difference."
"Not much of one," Issei muttered, but he didn't push further. He'd learned, over the past week, that when Dean decided to do something, there was no stopping him.
On the eighth day, Rias arranged the meeting with Shizuka. The witch's shop was exactly what Dean had expected: cramped, filled with strange artifacts, and smelling faintly of incense and dried herbs. Shizuka herself was a woman in her mid-thirties, with sharp eyes and a knowing smile.
"So you're the powerless human Rias wanted me to meet," she said, not bothering with pleasantries. "What makes you think you have what it takes to learn real magic?"
Dean met her gaze steadily. "I don't think anything. I know I'm going to learn, because the alternative is becoming a liability to myself and everyone around me. I'd rather die than accept that."
Shizuka's smile widened. "Good. That's the attitude you need." She gestured for him to follow her into the back room. "Let's see what you're made of."
What followed was the most exhausting day of Dean's life. Shizuka had him meditating, trying to sense the magical energy in the world around him, attempting to move that energy through his body. Most of his attempts failed spectacularly. But by the end of the day, he'd managed to create a small spark of light in his palm.
It wasn't much. But it was a start.
"Come back tomorrow," Shizuka said as Dean was leaving. "Same time. And bring a notebook. You're going to need to write down everything I teach you."
"How much will this cost?" Dean asked, suddenly aware that he had no money and no way to pay for lessons.
"Rias is already covering it," Shizuka replied. "Seems she's invested in your success. Don't waste that investment."
Over the next month, Dean fell into a rhythm. School in the morning, library research in the afternoon, and training with Shizuka in the evening. It was exhausting, but it was also exhilarating. For the first time since waking up in the hospital, Dean felt like he was moving forward.
His progress was slow compared to Issei's, but it was steady. He learned to sense magical energy, to manipulate it, to shape it into simple spells. Nothing flashy, nothing that would impress anyone in a real fight. But it was the foundation he needed.
And then, one evening, Shizuka said something that changed everything.
"You're thinking about this wrong," she told him as he was struggling to maintain a basic barrier spell. "You're trying to force the magic to do what you want. But that's not how it works. Magic isn't about force. It's about intention. You have to understand what you're trying to do on a fundamental level, then let the magic flow naturally to accomplish it."
Dean stopped the spell and looked at her. "Explain."
"Your problem is that you're treating magic like a physical skill. You're thinking in terms of muscles and effort. But magic is about the mind and spirit. You need to change how you think about power itself."
That night, Dean couldn't sleep. He lay in bed, turning Shizuka's words over in his mind. She was right. He'd been approaching magic like it was another form of martial arts, something he could master through repetition and effort. But magic was different. It required a different kind of strength.
The next morning, Dean went to the library and pulled out every book on meditation, philosophy, and mental discipline. If power came from the mind and spirit, then he needed to strengthen those first. Not just his body, but his entire being.
He started meditating for hours, not just trying to sense magic, but trying to understand the nature of power itself. He read about ancient monks who could perform impossible feats through mental discipline alone. He studied philosophy texts that discussed the nature of will and intention.
And slowly, something began to shift.
Two weeks later, Shizuka watched as Dean created a barrier spell without any visible effort. The magic flowed from him as naturally as breathing.
"There," she said with satisfaction. "Now you're starting to understand."
Dean felt it too. The magic was no longer something external that he was trying to control. It was part of him, an extension of his will and intention. And if he could do this with a barrier spell, then what else could he do?
"What's next?" he asked.
Shizuka smiled. "Now we teach you how to really fight."