DxD: DO System Chapter 46

Chapter 46: Training

[Days Later — Training Grounds, Gremory Estate, Underworld]

"Lady Rias, if you want to push out more power, you’ll need to be patient," Grayfia said, raising her hand as a swirl of icy magical energy formed above her palm. "Every kind of magic—whether it’s your Power of Destruction or elemental spells—requires precise control and exertion."

With a flick of her wrist, the swirl of demonic power shot forward, hitting a test dummy a few feet away. The dummy froze solid, covered in frost down to the smallest detail.

"And you already have the innate control from your bloodline," Grayfia continued. "That gives you an edge. You can manage the area of destruction better than most."

Rias frowned, staring at her hands. For most of her battles, she had simply unleashed the Power of Destruction as soon as it activated. There wasn’t much thought involved—she never needed to think about it.

The Power of Destruction was devastating enough to annihilate anything it touched, no matter how much energy she poured into it.

But deep down, she knew things wouldn’t be that simple against stronger opponents. Not that she’d had the chance to face anyone truly challenging.

Still, she’d figured out one thing: the Power of Destruction became more potent when more demonic energy was channeled into it. Even so, it didn’t behave like other magic or abilities.

Most powers could be compressed into dense, explosive forms or expanded outward with enough energy. The Power of Destruction? It didn’t follow those rules.

Its size was dictated purely by imagination. If she wanted, she could make it massive—larger than herself. But size wasn’t everything. The potency came from the demonic power fueling it.

You could create a disc or orb as big as an elephant, but without enough energy, it might not even scratch an opponent's defenses. On the flip side, overloading it could endanger allies.

It broke the laws of physics entirely, ignoring conservation of mass and energy. And one small mistake could mean losing something—or someone—forever.

Rias had been training harder than ever, pushing herself to grasp the ins and outs of her bloodline’s power while picking up some teamwork skills from Grayfia. During this session, Grayfia figured it was the right time to bring up something important.

"Lady Rias," Grayfia called, walking over to the heiress, who was sitting on the ground, chugging water from a glass bottle and catching her breath. "There’s something Lady Gremory suggested that might spark your interest."

Rias lowered the bottle, a tired but curious look on her face. "Honestly, Grayfia, I don’t think anything short of breaking this marriage engagement could motivate me right now."

Grayfia still continued. "She thinks this will interest you. It concerns your Power of Destruction."

Rias froze mid-drink, the bottle hovering at her lips as her expression immediately shifted to one of intrigue. Noticing she had the girl’s full attention, Grayfia continued.

"As you know, the Power of Destruction doesn’t come from the Gremory bloodline. It’s from the Bael blood you inherited through your mother." She stated what Rias already knew.

"And you’re also aware," Grayfia added, "that Lady Gremory isn’t an active fighter these days. She may serve as your father’s queen in his peerage, but she doesn’t participate in Rating Games or battles anymore."

Rias knew all of this already. Her mother had stopped training herself—or anyone else—a long time ago. After getting pregnant with her, she completely stepped back from the violent side of the Underworld. These days, she was a full-time mother, a devoted wife, and, when necessary, a political partner to her husband.

Her mother never gave a specific reason for withdrawing, but it was obvious she had no intention of returning to that life anytime soon.

“She suggested that if you win this Rating Game, you should visit the Bael Pillar,” Grayfia said.

Rias blinked in surprise. The Baels were known for producing monsters who could wield the Power of Destruction far better than she could. But still... she wasn’t thrilled about the idea of needing their help to master her own abilities.

Sure, there were Baels who could wipe out entire mountains with their power, and the elders of the Devil Pillars were some of the strongest beings in the Underworld.

But then there was her mother. The Brunette Princess of Destruction. She was the most powerful woman the Baels had ever produced before stepping away from the battlefield.

And her brother? Satan Lucifer, the Prince of Destruction. He wasn’t just powerful—he was probably the strongest wielder of the Power of Destruction ever.

Yet despite having two legends in her family, she had to turn to outsiders for training.

The thought stung. Rias couldn’t help but feel a twinge of jealousy.

Her mother had already accomplished more by Rias’s age. And her brother? She adored him, but she also knew she could never measure up to him—or even come close to his level.

Grayfia seemed to pick up on her thoughts which made her usually stoic expression soften slightly.

“Lady Rias,” she said gently, “you have more potential than almost anyone I’ve ever known. You carry the power of both the Gremory and Bael bloodlines. And you were born into a time of peace.”

Grayfia paused and her tone grew softer. “Your brother was born into a time of civil unrest. He grew up in an era when families were at each other’s throats. He had to fight to survive—to protect himself and others. That’s why he became so strong. It wasn’t just power—it was a necessity.”

This made Rias feel even worse about herself. She already knew she wasn't doing enough, but compared to Sirzechs —she felt she wasn't even worth it.

But then Grayfia said something unexpected.

“Your brother is strong, but even he isn’t perfect. He has regrets—not just in life, but about his powers.”

That caught Rias’s attention. “Regrets? About his powers? How could he have regrets? He’s the strongest there is!”

Grayfia surprised her by sitting down beside her. “He may be the strongest now, but he didn’t get to learn about his powers the way you can. He didn’t have the chance to be properly trained by your mother or the Baels. He was forced to fight before he could fully understand his abilities. He had to figure things out in the heat of battle, often improvising as he went.

“He believes that if he could start over, he’d learn things differently—maybe even reach a level beyond what he’s achieved. But it’s too late for him to go back now.”

Rias stared at her, stunned. She had never considered that her brother might have regrets. To her, he had always been the perfect embodiment of Destruction itself.

But even he had wished for more. That thought made her own dissatisfaction feel... more valid.

“You’re not even twenty yet, Lady Rias,” Grayfia said with a small smile. “You’re just getting started. You have the right teachers, the right environment, and all the time you need to surpass anyone who’s come before you.”

Rias looked down, taking a moment to process it all, then nodded. “Thank you, Grayfia.”

She gave the older woman a soft smile. “You’re always there for me, helping me feel better.”

“I serve the House of Gremory,” Grayfia replied simply. “I just do my duty.”

But Rias shook her head.

“No, seriously, thank you.” Rias gave her a bright smile. “You’re not just my brother’s wife—you’re like the big sister I know I can always count on. You’re family.”

Grayfia’s lips curved into a rare, soft smile. “You should get back to training with your peerage now, Lady Rias.”

Rias glanced over at her peerage, minus Issei, who were working hard and practically dripping with sweat.

“They’re waiting for you.”

Rias laughed lightly and nodded. “Yeah, I guess I should, huh?”

…

…

[Gremory Mountain Range, Gremory Estate, Underworld]

[Boost]

Issei felt his whole body giving out as he shouted his final [Boost], unleashing what had to be the strongest <<Dragon Shot>> he’d ever fired.

“Don’t lose focus!” Tannin barked. “Stay locked on the energy you just released!”

Issei was completely wiped, drained from all the Boosts and attacks he’d thrown earlier. Still, he gritted his teeth and pushed on, determined to reconnect with the draconic energy he’d just unleashed.

“Your power is part of you,” Tannin said firmly. “It’s hard, but not impossible, to take back something you’ve already thrown out. Find that connection and take control again.”

This was his seventh try, and he wasn’t about to fail now.

Gathering every bit of strength and focus he had left, Issei reached out for the energy. He felt a tiny spark.

It was weak—so weak—but he could move it. Just barely.

“Yes!” Tannin roared, noticing the <<Dragon Shot>> tremble. “Pull on it!”

Issei groaned, realizing how insanely hard this was.

‘Think of it like a toy,’ Ddraig suggested. ‘Like a yo-yo. Instead of trying to completely control the shot—which you can’t—focus on pulling the string to guide it where you want.’

Taking Ddraig’s advice, Issei pictured the shot as a yo-yo. He couldn’t steer it perfectly, but he could nudge it in the right direction.

“Yes!” Tannin roared again as the <<Dragon Shot>> shifted course, veering from one rock to another and smashing it into dust.

Issei collapsed to his knees, gasping for breath. “T-That... was brutal!”

Tannin chuckled. “Control is always harder than just letting loose, Issei.”

Over the past three days, Tannin had gotten used to the boy. Issei wasn’t like most devils. In some ways, he was worse, but he was also surprisingly easy to talk to.

He wasn’t as loud or obnoxious as Tannin had expected, and that made things... easier. The dragon found himself comfortable around the kid, and Issei, in turn, felt the same.

“I wish I was a Gremory,” Issei said with a bitter laugh. “This would’ve been so much easier.”

“Not everyone’s Sirzechs Lucifer, Issei,” Tannin said, trying to cheer him up. “Not everyone gets a bloodline that’s pure power and perfect control. But you’ve got the Boosted Gear, devil blood, and... something else I can’t quite put my claw on. Something that lets you pull off things no one else can.”

“Thanks, Ddraig,” Issei murmured, starting to realize just how much his powers meant for surviving in this world. ‘And you too, System.’

“Don’t mention it, kid,” Ddraig replied.

<The System exists to aid the host.>

“You too, Lord Tannin,” Issei said, plopping down on the ground. “Thanks to you, my demonic powers have improved a ton.”

“You’re getting there,” Tannin replied with a toothy grin that always made Issei a little uneasy. “Just a bit more push and control, and you’ll be teleporting like any other devil. But still, your draconic power’s skyrocketing, but your demonic power’s lagging behind. Not because you don’t have enough, but because your body isn’t trained to handle it properly yet.”

That caught Issei’s attention. “Wait, what? How does that even work?”

Before Tannin could answer, Ddraig chimed in. “Kid, do you think I don’t have enough power to crush most of the people around you?”

“You definitely do,” Issei replied without hesitation. He wasn’t sure how Ddraig would stack up against someone like Sirzechs, but he knew the Heavenly Dragon could wreck a lot of the devil world if he wanted to.

“Then why can’t you use all of my power?” Ddraig asked. “There are two reasons. Think you can guess them?”

Tannin jumped in to explain. “Your body, Issei, is like a reservoir. Ddraig could give you all his power, but if your reservoir isn’t big enough, you can’t hold it all.”

“The second reason is your output,” Ddraig added. “If your storage is full but the exit is tiny, it’s inefficient—and dangerous. The power would force its way out, and you’d risk seriously hurting yourself.”

Issei frowned, a little uneasy. “Okay, so what do I do? Which do I work on first, and how?”

“It’s all about training,” Tannin said. “First, you need to improve your body—expand your storage. Your body is your weapon; it’s where everything starts.”

Issei looked at his hands, thinking it over. He’d gotten stronger, sure. His muscles were bigger, and he even had proper abs now. But it still didn’t feel like enough. He knew he could push his body further—make it tougher, stronger, more durable.

“The stronger your body, the more demonic power you can handle,” Ddraig added. “And once you master control, your output improves, too. That’s how you get better overall.”

“So that’s how I improve my devil class, huh?” Issei asked.

“Exactly,” Tannin said. “Not socially—but definitely physically.”

Issei flexed his arm, still pondering. “Okay, but what about improving my exertion? How do I get better at that?”

“That’s where your mind comes in,” Tannin answered. “Your imagination, your perspective, your mindset.”

Issei stood up, still confused. “Wait, are you saying… I can’t imagine stronger attacks?”

Ddraig corrected him. “No, it’s more like—you’re not imagining them.”

“Huh?”

“You’re scared,” Tannin explained bluntly. “And before you argue, it’s not something you consciously do. It’s buried deep in your subconscious.”

Ddraig continued, “It’s a safety mechanism—your mind’s way of protecting you. You’re worried, even if you don’t realize it, that pushing too hard could hurt you. It’s not a bad thing—it keeps you safe.”

“But if you want to grow stronger, faster, you’ll need to let go of that safety net,” Tannin finished. “That’s how you’ll improve both your draconic and demonic power.”

This was news to Issei, and it left him curious.

“So, how do I do it?” he asked, determined. “How do I get rid of this safety lock?”

Tannin grinned widely, and Ddraig stayed silent. Seeing that, Issei knew he was on the right track of improvement.

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[[A/N: Will post another chapter of this + 1 chapter of Marvel in an hr. ]]