Upon reading the comments, I realized I almost turned this story into some weird generic MC thing combined with mental gymanstics. That won't do, this is supposed to be a somewhat edgy story about someone using smarts, magic, and some luck to do stuff in DxD. I'll have to fix this, so the original ch 2 and 3 have been deleted. Thanks for understanding.

And thanks for your comments, they let me recognize these kind of things.

Once upon a time his parents left an inheritance after passing away. Enough money for him to live comfortably and afford a college to get a good job. He doubted he'd have actually spent it doing that, even if his parents had stayed alive, but the idea was worth keeping in mind.

He didn't know this.

He had been adopted very early on by his uncle and aunt, and knew them only as dad and mom. He hated them.

"Are you sure you want to spend your time lying around all day? We won't support you forever. You have to get a job." Said the mom that used his money to replace her car every six months and fund trips only she wanted to go on.

"Once you're a grown up, you'll have to get out of this house. You should be studying and getting ready to start your own family." Said the dad that gambled his money every weekend and came back penniless more often than not.

Relatively speaking, he lived a content and peaceful life. He didn't enjoy many luxuries, those were exclusive for the adults as it was the 'fruit of their labor'. He got treats here and there, keeping him in line was important for the adults after all. But he had grown used to the small things in life. Things like scanning mom's bills or taking photos of dad in the casino. He never understood why one of his teachers suggested this, but he felt it was a form of revenge on their excess that hurt nobody.

The teacher, as it turned out, used to be his actual dad's accountant.

As it turned out, through a series of rules in the inheritance, he could get everything back and sue those two for everything they owned once he became an adult.

Realizing he had been ensnared like this hadn't been fun. He felt like a reverse cuckoo, kept in the parasite's nest to be fed on. His parents, and the children they had, leeched off of the fruit of someone else's labor. Fruit which he, and only he, was entitled to.

He hadn't always been twisted, some time ago he had been a bright-eyed kid with a smile on his face. Sure, his parents weren't perfect. But everyone had problems at home, some less and some more. But his home was fine enough.

Right?

The fact that he would rather spend his time alone and away from everyone was simply a personality quirk. Even his siblings thought he was a bit of a weirdo, but everyone had these tiny bits that made them different. Not always in a good way, but that's simply how people are.

"Son." His so-called father called out one night. It was strange for the man to drink, much more to have a moment of rage in the house and storming off to drink.

That man wasn't like that, and the son simply hoped this wouldn't be a recurring thing. He didn't want to also have to fill a complaint that the man had become a violent alcoholic.

"Yes?" The son arrived at the kitchen, seeing the man sit while cradling his head. The man reeked of alcohol.

"Sit down son." The man said before sighing "Son, I want you to know something. It's maximally important that you hear me out. Don't make the same mistakes as I did."

Okay, that was new. But the son had no other choice but to listen. It was irritating, but listening to the rambling of a drunkard only went that far. He hated the man, but it wasn't the time to lash out yet.

"Listen son. No matter what you do, be careful with who you trust. People will always try to backstab you, they'll try to take what is yours because they're petty, narcissistic, and greedy like that."

The son's mind blared with alarms.

"Isn't that right, you fucking bastard?" The man took out one of the USBs the son used to store the incriminating antics of his parents.

The Khaos Brigade had quite a few high ranking devils amongst its ranks. Individuals that wanted power more than they respected it, which in turn made them envious and resentful: Easy targets for the old Satan faction, whose ideals were all about regaining the power and status they lost.

Mostly males, because of course that's the case. Why would they make potential harem members be selfish or power hungry? That doesn't sell figurines.

But that no longer concerned Diodora. He didn't want to throw himself in danger needlessly to woo someone into being an unconditional follower. Because while the logic of this world said it could work, Diodora didn't have a broken power that would get him out of trouble. He almost paid for the original's foolishness once, he didn't feel like risking it by his own will.

Besides, he already had his hands dirty by inheriting a membership to the de facto terrorist group of this world, he didn't need to run headfirst into trouble too.

"Diodora." A beautiful man with long chestnut hair approached. Wearing dark armor and beaming with pride, this descendant of the old Satans looked displeased with Diodora appearing in the Brigade's hideout.

"Lord." Diodora bowed, going midway to a one-knee reverence. He suspected why this man looked so mad at him. But presented with someone so much more powerful than himself, Diodora could only behave himself.

"It seems Katerea's scolding did its job. You've been a lot more involved as of late." The devil's words made Diodora clench his jaw.

There had been no scolding. Only the Leviathan heiress letting out her frustration on Diodora with no way of being stopped. He could feel phantom pains in his muscles, and a shiver ran down his spine at the memory of her presence itself sending out so much pressure he could barely move.

Still, the older devil didn't look pleased with this. As it turned out, he had been the one to get the original Diodora involved with the Khaos Brigade. Letting him do whatever he wanted and covering for his misdeeds as he kidnapped nuns right under the church's noses. It made sense, since it stirred the flame of conflict in an indirect way. And in turn made the original Diodora an easy pawn to control, being someone controlled by his urges. But the current Diodora had no such inclination, and had gotten rid… Err, lost his women in the incident that got Katerea to almost kill him.

Diodora understood that this man didn't like his leash being gone, and probably hated the idea of Diodora growing ambitious now that he had been 'set to the right path' by almost dying to the church and Katerea's punishment.

It didn't make it easier to process, given the metaphorical scars. But at least it gave Diodora some reference. A small mercy if almost dying offered one.

"I've reflected on my shortcomings." Diodora muttered, letting his voice be tainted by the ugly feelings swelling in his chest. He wouldn't be able to cover it up anyway, and it might be suspicious if he did succeed. So he didn't think too hard about it.

The brown haired devil nodded, letting the silence stretch as he studied Diodora. The way he died didn't come to mind, but it had probably been at the hands of Sirzechs or Ajuka.

Shalba Beelzebub. To think the current Diodora had once mistaken him for the Asmodeus heir, and with the original Diodora too... He was that unimportant in the grand scheme of things, but he looked so impossibly self-assured once they met face to face.

How would this Demon Lord wannabe react if he knew of his destiny?

The thought helped Diodora stand his ground, staring back against the more powerful devil.

"Is something wrong?" Diodora finally asked after a minute or so.

"It's come to my attention that you're bolstering your peerage." Shalba replied easily enough. Frown still on his face, and crossed arms to boot.

He didn't need to spit on the ground, he almost dared Diodora to challenge his attitude with his body language alone.

As expected of someone this petty.

"That is correct, milord." Diodora lowered his head and closed his eyes. Not out of respect, but because he grew tired of facing so much disgust directed at his person.

Something was definitely wrong if Shalba chose to dodge the question like that…

"Wuh?!" …So of course Diodora found himself grabbed by the neck moments later.

"Destiny calls for us." Shalba tightened his hold, making Diodora arch his back as the pain disabled him from doing anything but struggle "I took you in because I saw potential in you, but you ought to prove that you won't drag all of us down. Only the worthy and powerful will rule in the new world. Are we clear?"

Diodora kicked the ground, grabbing the hand that held him and trying to peer it off to no avail. His throat got crushed a little harder.

"Do you understand?" Shalba repeated himself "Or are you disposable after all?"

No one came to Diodora's aid, as no one passed through the hall they were occupying. And even if someone did, no one would choose to help him. Everyone detested devils, and they would choose to ignore the weak as well. So Diodora was alone to fend for himself in this situation.

He used his demonic power to push away the pain, to give himself some respite even through his lungs lacking enough oxygen to think. It came to him almost involuntarily, a form of muscle memory that transcended the new soul inhabiting this devil body in an attempt to keep it alive.

When his mind clicked in place, Diodora grinned.

"Ri… as…" He wheezed.

Shalba hardened his glare.

"What?" Was Shalba's brain lacking oxygen? Or was he naturally this stupid?

Diodora suspected the latter, but maybe Shalba was the kind of person to stop breathing when he saw someone else do it? Some children did while watching movies, and the people of this world had never been particularly smart.

Oh, well. Diodora had no choice but to help along that tiny brain of Shalba's.

"You have… No way of fighting… Sirzechs…" Diodora used his demonic power to toughen his skin and push air into his lungs.

For all of Shalba's might, his physical abilities weren't anything to write about. Sure, he'd beat up Diodora due to the inherent unfairness of demonic power. But he'd have to aid himself with it if he wanted to beat Diodora in this situation.

Sure, Shalba still kept him pinned while Diodora desperately fueled his struggle to come close to matching an unaugmented Shalba. Sure, that could be seen as defiance and a stupid move. But it wasn't about defying him here.

It was about pride. Shalba, and the other old Satan inheritors for that matter, were prideful to a fault. And they would never let themselves be seen having to put effort against those they perceived as lesser than themselves.

"You dare…" Shalba knew it too, he just didn't want to admit it. Hurting his pride was a really foolish move, but Diodora already was taken for a fool. He didn't have much else to lose.

…Other than his life.

"I have access… To what Sirzechs treasures the most…" Diodora's grin widened, making damn sure this Demon Lord wannabe knew he was completely serious "I can… Make it so… He doesn't have to… Be fought…"

Of course, reality was different. Even if they used Rias to bait Sirzechs or break his will to fight, in the end the gap in power was simply too large to actually pull off. Having the Power of Destruction already turned him into an incredibly broken character, but being the strongest Super Devil on top of it simply made it impossible to be taken down by conventional means.

Given the segregation between groups, the Khaos Brigade would never be able to defeat Sirzechs. Serafall, maybe. Ajuka… Unlikely, but he didn't belong to the same household as the main heroine; so it might be possible. But Sirzechs? In the original timeline, he had to be sealed away with 666 just to let Issei take on the bigger leagues. He was just that broken.

But Shalba didn't know any of this. Not in the way Diodora did, at least. He simply saw Sirzechs as the challenge he'd have to take on. Maybe not personally, but at least as part of his personal goal of destruction and domination. The final boss, in a manner of speaking. Which he couldn't afford to think of as undefeatable lest he went insane due to his pride.

For all their power, smarts didn't list among devils' strongest traits.

"Why should I believe you? What makes you think your relationship with the Demon Lord's little sister is worth keeping you around?" Shalba didn't let go, but neither did he add any demonic power to his hold.

In his previous life, Diodora hadn't been able to talk his way out of this kind of situation. So he raged against it. His mind, his very soul, demanded that he fought back to the bitter end.

He used some demonic power to force his body to calm down, to keep working. It almost pained him as much as Shalba's hold. To deny himself something he wanted so desperately was a pill as bitter as anything he had tasted. It went against his principles, his way of life.

So Diodora kept on grinning. He put all of his defiance on his attitude, his voice. In time, Shalba would be gone. But if he wanted that time to come, Diodora needed to shake him off now. To make this devil see that he wouldn't be able to boss Diodora around life before.

"In time, you'll bring out the full might of the old Satan faction." Diodora managed to say, feeling Shalba's finger being unable to keep up with Diodora's demonic power "But tell me: Do you intend to fight honorably? Are the current Demon Lords worth the courtesy?"

Shalba didn't reply immediately, so Diodora kept going.

"I figured it out while surviving against the current host of Excalibur Destruction: Nobody wants to admit it, but we're severely outpowered—!"

Shalba finally put some demonic power into the hold, making Diodora groan in pain.

"We're mighty enough!" The devil said.

Diodora changed gears, trying to conjure his voice directly with magic instead of breathing with it.

"Sirzechs Lucifer! Michael! Hell, even Vasco Strada!" His conjured voice sounded almost as choked out as he felt "We're surrounded on all fronts by…! Enemies…! Enemies that don't deserve…! A fair fight…!"

"So you say." He couldn't see Shalba with his eyes screwed shut, but he sounded more offended than pissed off "But that doesn't answer my question: Why does your idea make you worthy of keeping?"

Diodora's strength slowly left his body, going limp as his lungs burned due to desperately needing to be filled. He mustered some of it to lift a finger from his left hand, and it took all of his smarts to not make it the middle finger.

"En… vy…"

He couldn't see him, but Diodora could almost bet Shalba looked puzzled.

"...What?" Shalba's demonic power ceased, and the hand around Diodora's neck disappeared. Letting the raven haired devil drop to the ground in a coughing fit.

Demonic power filled his body, fighting off the natural impulse to take in as much air as possible. Diodora caressed his neck and tried to center himself.

In due time, Shalba would be gone… He just had to be patient… He couldn't be… As stupid as he was…

"Envy." Diodora spoke with his own voice again, raw as it sounded "I've… Observed Rias Gremory for a bit. And heed my words: I believe she can be made to pursue her older brother's exploits."

Anyone that knew Rias for a bit would've laughed at Diodora, mocked him for the wildly inaccurate portrayal of the redhead he presented.

They would be fools.

He didn't have to be accurate. He needed to present her in a way that Shalba could understand. Because his skull was too thick to comprehend that his cause was doomed to fail he seeked excuses. Half-truths and explanations that fit into his vision of reality. He, and Katerea and the Asmodeus heir for that matter, hadn't made any plans that would realistically work whatsoever. They rested in their high thrones, content of bossing the lesser devils around and talking about their incoming raise to power.

And the other devils played along. Because it gave them the power they wanted to forward their own agendas. Maybe some really believed the time would come and prepared to act accordingly. But everyone in the devil faction had joined for their own selfish reasons. Just as the old Satan heirs took advantage of Ophis for her power, so too the lesser devils did the same to them in search of what they wanted.

If left alone, the Khaos Brigade would fail because no one had the right attitude to gather all of their resources into a realistic plan.

And Diodora liked it that way. Because it made his lies and half-truths all the more believable.

"To make his little sister fight him…" Shalba put a hand on his chin. Diodora's offense already forgotten "And if we back her up from the shadows…"

"Are you interested in meeting her?" Diodora clenched his jaw, talking without meaning to.

It'd be the height of idiocy. To allow Shalba to meet Rias this early would do nothing but cause a catastrophe. She most likely knew of him, and that was probably the reason why Shalba specifically mentioned doing things from behind the scenes.

Still, his neck swelled from the manhandling and his lungs burned almost as much as his hatred. He needed to get back at this lunatic no matter what. It ate away most of his reasoning, only able to stop himself from snarling by sheer force of will alone. Will to keep living that is, because this devil could still get set off by Diodora's attitude.

Not now. Give it time.

Shalba scoffed.

"You must think I'm a fool. There's no way you've bewitched the heiress of Gremory so soon." He turned around and walked away. Talking like this almost as if he was trying to look cool "Perhaps later on… I look forward to your endeavors."

Diodora clenched his fists.

Had he doomed himself? Unlikely. This early on anything could be a danger, no matter how insignificant. But doom meant he had completely screwed up in a way that put him in the center of the heat. And while Shalba could indeed become one of the worst threats to Diodora, he had also been cunning enough to try to manipulate the original version of him.

Did Shalba figure out something was amiss? It felt more likely this time around. Diodora didn't know enough about this old devil. Only that he supposedly wanted to annihilate and conquer everything and anything: A simple villain. But that couldn't be all. One didn't just see their dreams come true just because they willed them strongly enough, devil or not.

Perhaps he questioned why Diodora stuck to the Khaos Brigade. Without the original's motivations, it made sense that he'd try to run away. At least in a sense. Because the original Diodora was just a small fry, and behaved as such for the whole duration of his screen time. Even begging to be saved once Issei fought him for real.

Perhaps Shalba suspected him… No, Diodora could almost be certain of it. No one changes overnight, not even after an encounter with death and a terrible beating by their 'boss'.

Diodora wanted to think that the invitation to go see Rias would deter Shalba a bit, make him think something would happen if he did do it. Maybe it'd even make him think twice before sending someone to spy on him? That'd be optimal, but he wasn't sure where shonen anime stupidity ended and real life logistics started with the people of this world.

Sometimes it felt like only one existed, then some others… Well, it felt like a flip coin. One he didn't want to take.

He shouldn't have said that. It only made things more difficult for him.

He kept kicking himself over losing his cool while returning to Kuoh.

"Ah! Dora-chan~!" After having wasted time with Sona for two weeks, the elder sister of the Sitri appeared.

"Good evening, Lady Serafall."

Serafall Leviathan looked as cheerful and charming as he suspected. Not dressed in her magical girl outfit, fortunately enough, but still getting a lot of attention as this beautiful girl beamed and radiated happiness all over the place… To think all he had to do to make her appear was get close to her little sister. Serafall had enough power to be given a Demon Lord position beside the likes of Sirzechs and Ajuka. Diodora didn't quite know what the roof of her abilities was, but he didn't feel like figuring it out. Seeing her face to face made him know almost instantly that her existence couldn't be fought at his current level.

And in his rage, he had hoped that Shalba couldn't either.

Diodora's stomach turned. He hadn't thought about how he'd explain popping up with an old Satan faction devil, but at the moment it hadn't mattered. All that he cared about was utterly destroying that bastard, to see his face when he realized that he had been led into a trap. That he had been outsmarted by the small fry he wanted to control.

He still did, but after gathering his thoughts it sounded like an awful plan. Maybe Shalba had known Serafall arrived at Kuoh recently, or it just sounded suspicious to get the offer so suddenly. Diodora wouldn't know since he was being strangled at the time.

He stopped himself from clicking his tongue. How much easier would it be if everyone acted carelessly? Even if they weren't that smart, Diodora couldn't just lower himself to their level. He lacked power and resources. But that wouldn't be the case for long.

"How has Genshirou been? I hope Lady Serafall wasn't too rough on him." Diodora has trouble smiling, as he felt Shalba's hands around his neck like a curse activating. Still, acting had to be done so he powered through it.

"He's great! I was spoiled a lot while you were gone~." The Demon Lord beamed as Diodora offered her his arm. She intertwined hers around it, and led the way.

She was a lot more charming than her little sister, and probably more cunning as well. Diodora pretended not to notice the side glances she gave him, probably noticing that something had happened to him. Yet she chose to stay quiet.

Another problem, perhaps. But one that would simply go away when she realized he had no interest in her sister whatsoever.

"How was your trip? Where did you go?" Serafall asked, looking around instead of at Diodora while she talked.

"I went to Broadway." Diodora lied with a chuckle "I heard today's play would be good, and kind of messed around for a bit."

"Eh~. Why didn't you take Gen-kun along?" Gen, huh. Did he leave such a good impression on Serafall?

No, concentrate. He was probably reading too deep into things due to the incident with Shalba. He couldn't just jump at shadows all the time, it'd wear him down. If Genshirou left a good impression on Serafall, that was a win in Diodora's book.

"I promised him a normal life." He replied with a stern face "It makes things difficult, as I didn't plan on overstaying the girls' courtesy. But I'll figure it out. For now, he should be going to school and doing things humans his age do."

On top of training, because Diodora wanted to add Absorption Line to his list of training tools sooner than later. If things worked out, he'd be able to use Genshirou's Sacred Gear to boost his demonic power, draining it during training and taking it back afterward.

But he needed that Genshirou had more proficiency in it first. So Diodora interrupted his own training to let the boy take most of his power and keep it.

Issei had grown really fast during the original story. So Diodora hoped that, with a year of headstart, Genshirou could achieve the same if not more.

"Heh~. I always knew Dora-chan was considerate, but…" The Demon Lord sighed, still having her arm around his.

Diodora knew the original had hardly covered his preferences. But Rias and co had looked surprised when he was revealed to be evil. So maybe it wasn't that evident?

Again the balance between how he remembered everyone being dumb vs how they seemed to pick up certain things now that he walked among them.

Food for thought, as most things were nowadays.

"Besides," Diodora chose to change the topic. The mental injury was still fresh, so he didn't want to dwell on it for too long "The play was really weird. He might not have liked it."

"Really? What was it about?" Serafall readily followed along. Diodora suspected she was letting him get away from the uncomfortable topic.

"Cats." He replied, almost sighing in relief from the respite "Regular cats. Except one of them can do magic? And another one kidnapped an older one? It was pretty confusing, not going to lie."

They went to the old school building, where the girls would be gathering. Diodora supposed that the Demon Lord wanted to observe him around Sona again.

And for now, he was glad to comply. At least it'd keep his mind busy from obsessing about ways to keep Shalba before they got to the time the story started.