Mantle

You crash through another wall as Arthur tries to swing at you using his blade.

"Be careful, that sword can cut straight through your armour!"

You didn't need to hear that to know. This is one of the most legendary weapons from the world of DxD. Your mind scrambles for a quick fix to this problem. The copy is getting away, or potentially even planning to attack Issei with Vali before we can get there to back him up. You duck another swing and kick the carcass of a burned car at him, forcing him to cut it in two to avoid being knocked aside. During that moment of opportunity, you are already loading two cards into your gun.

"XENOVIA QUARTA, SHATTERING!"

"KONEKO TOUJO, SHATTERING!"

Arthur's eyes widen in unbidden surprise as Xenovia and Koneko appear from thin air. There's a pause as he tries to recalculate his odds of victory, and as they both try to get their bearings from being summoned so suddenly.

"So this is what Rias meant," Koneko frowns. She must have been updating them on the fight using her phone.

Xenovia doesn't care – she's just pumped to pick a fight with Excalibur; "Finally, a battle worthy of Durandal!" A large blue sword appears from a magic circle, which she wields with confidence and skill.

"Sorry – can you two keep this guy occupied? Issei's in trouble."

"Very well," Koneko nods, getting into a fighting stance. Xenovia has already launched herself at Arthur before you can even finish explaining the situation. They clash in a shower of sparks and with the heavy clang of metal meeting metal. Koneko dons her gloves and leaps into the air, coming down with a vicious spinning kick that forces Arthur to reposition and cracks the ground beneath.

You turn tail and run towards where the most noise is being made. A building explodes overhead as a pair of coloured streaks fly through the sky and come back down in the middle of the intersection. Issei kicks Vali up off of his body and forces him back, but it's clear that Vali has gotten the drop on him this time. Issei cannot damage him with his power divided so heavily.

"Just give it up, Red Dragon Emperor. This fight was over before it even began. You can't hope to injure me with your powers weakened like this."

"Damn it!" Issei swears, punching the ground in frustration, "This is so uncool!"

Vali turns to face you as his summoner emerges from the background. "I'm willing to accept your unconditional surrender, and an apology to my dear lady for your boorish behaviour."

You shake your head, "Man. You really are one lame ass-kisser. What happened to that individuality of yours?"

Vali laughs, "I do what I do because I want to do it. My lady is an unparalleled beauty, of whom I would happily take her hand in marriage. Are you not doing this for the same reason?"

"I'm doing this to protect the Earth," you respond. Your UI triggers and the mantle card is ejected into your hand. "This fight isn't over just yet. Not while I'm still breathing, and certainly not while there's still aliens left to beat!"

"Bah, more parlour tricks."

"Don't look away – this one might shock you."

You slide it into the newly added slot on your left arm. A mechanised roller accepts the tip of the card and swallows it whole, as it does, a new touch screen appears on top which displays it for you to see. You slide your fingers up and over to confirm your selection.

"MANTLE! Boosting Dragon!"

An orchestral jingle plays thanks to Mitsuru's touch for the dramatic.

The stained glass that covers your body shatters outwards, exposing the internal systems that lay underneath. The floating shards shift and realign into new shapes, before turning entirely red and slamming back down onto your frame. A wave of excess energy shoots outwards, kicking up a fresh cloud of dust that obscures everyone's vision. When it finally settles an entirely new form of the Herarmor is on show.

An unseen speaker blares a rote catchphrase: "Shattering foes with explosive power!"

Did Mitsuru hire some guy to voice-act for this thing?

You glance to the left and spot your reflection in one of the few remaining shop windows. The previously non-descript features of the armour have changed to more closely resemble Issei's. The white under suit is now interspersed with recoloured glass panels, a deep, vibrant red. Your visor has turned green, and now bears a new silhouette that imitates his own helmet.

Vali is not impressed by the display, "Changing colours isn't going to save you."

"This isn't just a change of clothes," you smirk. The charts on your HUD are going haywire as it tries to calculate and adjust for your new-found strength.

Mitsuru speaks, "While this new Mantle is extremely powerful – I would recommend against fighting Vali directly. He is a god-like being after all. Pushing your body any further than this would tear it to shreds."

You close the circuit so he can't hear you; "So what should I do?"

A new card appears on your screen, one that showcases you throwing out a bolt of green energy against an exploding background. You go along with Mitsuru's plan and eject the card into your hand, only to slide it back into a different but identical slot…

"Isn't this a little redundant?"

"I didn't get the chance to optimise the system yet!" she yells, "Transmitting and reading data are two different jobs you know!"

"Boost!"

Mitsuru explains, "Since your body can't handle more power than this – this card is perfect for buffing your summons."

A burst of green flame engulfs your gauntlet bearing hand, a circular orb slowly starting to form in your palm. Vali just scoffs and holds out his arms to catch it, believing earnestly that he can simply block the attack and be done with. Issei is struggling to climb back to his feet behind him. That confidence is going to be his downfall.

"Take this!"

You wind up and unleash your best throw. The flaming ball flies through the air and approaches Vali at an incredible speed, but at the last second it begins to drop down, flying between Vali's legs and striking Issei instead. He bursts into green flame. Vali turns back and begins to laugh, "Is that it? You just hit your own companion! You damned fool!"

Only for him to be sent flying through the side of a nearby bus a moment later. Issei is back to full power, and now Vali's hard work has been undone. He flies over to you and shakes your hand with so much **** that you think he's about to accidentally rip it from your body.

"Thanks!"

"No problem."

Issei looks at your new armour, tilting his head to one side; "I've seen this somewhere before."

"Heh. Imitation is the sincerest form of flattery and all…"

Issei laughs it off, "Just don't leave me out of the action. I'm always down to beat up some bad guys!"

"Don't worry Issei – your body can handle a lot more than mine. It's going to be hard to replace the genuine article."

The pile of scrap metal and rubble that Vali has been thrown into explodes outwards. He roars in fresh anger. He knows now that the odds are starting to turn against him. You've restarted things, and now Issei has you for backup.

"Cheap tricks! Is this all you have?"

Vali charges at you with blinding speed, but for some reason it feels like you can keep up with him more easily now. What was once a smeared blur of white and blue is now more cognizant to your human eyes. It's a punch! You duck the blow and retaliate with a kick to his left side. It isn't the explosive blow that Issei can deliver on demand, but it knocks him for a loop that you're now capable of defending yourself against him.

Issei is quick to follow up, beating him down into the ground with an overhead punch. The ground cracks and opens up beneath him, leaving a long trail of destruction. When the dust settles, Vali is breathing heavily with a serious crack in his armour. Another explosion rings out, Arthur Pendragon trying to defend himself from both Koneko and Xenovia. You were worried about the difference in strength between them, but it seems your fears were unfounded.

He backs away from them and lands next to the injured Vali, "Apologies. It seems that we've been outmatched on this occasion."

During all of this, your evil copy has been standing there doing nothing. It looks like she is unable to handle the pressure when things get out of her control. "I'm sorry," she mutters. She turns the barrel of her gun and sends her injured servants back to their original dimension. If she wasn't careful, those injuries could become much more permanent. But now she is left with nothing. There's little realistic prospect of her beating Issei without Vali around to divide his power.

"I'll ask you again, why are you doing this?"

She stamps her foot and raises her voice, "Because I want to have a harem of anime boys! Is there something wrong with that?"

"When you're trying to help some alien assholes conquer the Earth, there is something very wrong!"

"Ugh. What difference does that make? What can they do to us that's any worse than the leaders of the world as it is now? Hell – they might just improve this dump by letting us use their advanced technology."

She's trying to wash her hands of the responsibility; "Or we could just steal it and reverse engineer it for ourselves, sounds easier to me."

Issei nods, "Yeah – what he said."

Xenovia and Koneko approach from behind. Man, you really summoned a lot of DxD characters, didn't you? You need to spread the love to some other universes soon.

Koneko is cold-blooded, "I thought that he was the biggest pervert here, but he has more respect for the people living on this planet than you do. You're willing to harm many innocent people just to satisfy your sexual urges."

"I don't want to hear that from you! You summoned DxD characters as well!"

You scoff, "That isn't the point. You can only do the same because they stole that technology from us – and in return they want you to do whatever they demand. When they start telling you to kill people for real, are your excuses gonna' work the same then and there?"

She points at you as if to continue the debate, but the words die in her throat. She knows that there's no defending that position from you. As pretentious as it sounds, you're on the side of justice, while she attacked a major urban area for no good reason. No doubt one of the enemy officers told her to destroy you.

"Next time, I'll win."

A wormhole appears beneath her feet and sucks her into the ground. It looks like that's all from her for today. You detach your armour and let out a weary sight. That took a lot out of you. Xenovia glances at you from the corner of her eye. Issei speaks first, "Uh. Could you send me back? I think my girlfriend might think I'm cheating on her."

What kind of magic did Mitsuru use to find an Issei who's faithful? Or is she really just that scary?

"Sure. Catch you later, Issei."

You insert his card into the Sledgehammer and dismiss him. You turn and start walking away from the scene before the police show up, but Xenovia gets in your way. She's shorter than some of the other girls. The leather outfit she wears shows off all of her amazing curves.

"Before you go, I'd like to bill you for my service."

"Bill me?"

Xenovia closes her eyes and crosses her arms, "Three or four children should suffice, dispensed over the course of two to three years. A sultry sum of payment for my skill in battle, wouldn't you agree?"

Of course that's what she wants…

"Rias might have a thing or two to say about being second place in the baby making contest," you joke.

"Then she is at fault for not starting sooner. A strong male is perfect for producing heirs; she should simply become more proactive if she finds my methods distasteful." The sirens are getting closer and she's arguing with you about who gets what number of babies first.

"Can we have this talk another time? Preferably with your master in the room?"

"Hmph. Be cautious, a significant delay will incur interest payments."

"Interest payments, paid in children?"

"Yes, exactly."

"Pervert," Koneko grunts; not aimed at you for the first time.

"Okay. Good talk, see you girls later."

You hurriedly de-summon them before you get arrested for causing all of this damage. You knew it was coming, but actually experiencing Xenovia's odd fixation on having children is another thing entirely. You don't know how you're going to deal with her in the future. For now, you just need to worry about staying out of jail. You leap onto your bike and take off.

When you return to the garage for a debrief with Mitsuru, you find her standing over her workbench with an action figure in hand. Between you using the new form for the first time and the ten-minute drive back – she has somehow managed to design and 3D print a prototype product to coincide with its debut. She hastily shoves the shameless merchandising into the drawer and snaps up to stare at you as you dismount the bike.

"Good work. I managed to gather some interesting data about the joint tolerances of our armour system."

"Didn't you say I'd snap in two like a twig if I went any harder than that?" you ask. Your whole body feels like it's been put through the wringer, and all you did was deflect one of Vali's attacks.

"Oh yes, that is a concern too. We cannot push the mantle any further without risking daage to your body – though at these output levels it would be a pulled muscle or dislocated bone, not a full-bore removal of one of your limbs."

"Well, I'd rather not have to experience that regardless."

"Asia can heal you. I think."

"Again, I'd rather not."

Mitsuru adjusts her glasses, "Naturally, there are limits to what the human body can withstand. The scale of the threat we face has expanded rapidly beyond our control. Especially considering that our new rival dived right in and summoned Vali Lucifer of all people. This is not a hurdle that can be surpassed with simple training."

"So what could make me stand toe-to-toe with him?"

"Supernatural power? Things that defy the laws of our own physical reality, whether that in itself comes through effort or outside manipulation is ultimately up to us. Rias still has some of her evil pieces, does she not?" Mitsuru is right. It seems that Rias has yet to recruit Rossweisse into her peerage. That means she has a spare rook that could theoretically be used on you.

You scratch the back of your head and sigh, "Feels like a big leap to take."

"The fate of the world is at stake! And what do you lose by becoming a devil anyway? I've never once known you go into a church."

"My humanity!"

Mitsuru shrugs, "Humanity stinks; we don't even get cool magical powers like they do. What's the downside, honestly? You could turn yourself into a devil and not a single soul would know about it unless you told them."

Mitsuru has always had a strained relationship with what most people consider normal. She's an anti-authoritarian at heart. You've seen her get hopping mad whenever you accidentally leave the news on and some politicians says something she doesn't like. She thinks that people should do whatever they want as long as it makes them happy. In this case – ending your life as a mortal human and becoming a devil.

"I don't know – it's just... I've spent my whole life being human. It feels weird to just dive headfirst into not being human when we've done just fine so far. Issei only turned into a devil after he got killed, and having an 'extra life' sounds pretty useful to me."

Mitsuru shakes her head, "Wouldn't it be safer to be strongest now than wait until a hypothetical defeat? What if Rias can't reach you in time? What if something terrible happens to your body and we can't revive you?"

We.

That explains a lot. Mitsuru is honest but never directly. She's not as good at hiding it as she thinks. She's worried that something bad is going to happen to you, but even more then she's letting on with you right now. Lumping herself in with Rias and the others indicates that her feelings are stronger than she acknowledges. Sensing that she had left her heart on her sleeve, Mitsuru clams up and waves her hands; "N-Not like I'm your fiancé or anything! As a friend, I'm worried about you as a friend. And the fate of the world is at stake here! Something as nebulous and meaningless as 'humanity' is a small price to pay to succeed."

You sigh, "But there's more to being a devil than just being given the evil piece. I'd need to form contracts and play rating games to get stronger – which we can't do here."

Mitsuru ponders it for a second before snapping her finger, "If I could find a way to transport you to their world, that wouldn't be a problem. Rather, that's something I've been planning for some time now."

That sounds like a huge leap from where your technology is now, but if she gets the proper tools and resources...

"Are you sure that won't have unintended consequences?"

"I make extra sure that all of my work is fail-safe and fool proofed, after all, the biggest fool I know is walking around with a dimension sundering gun right now."

"Gee, thanks."

Mitsuru unfurls a large blueprint onto the desk, which reveals an elaborate piece of underground machinery connected to a thin, door-frame like device.

"The idea is to create a less mobile version of my interdimensional portal technology that will allow any number of permitted individuals to pass through. Of course, it's significantly more expensive and labour intensive to create – requiring a matching portal device on the other side to allow for the trips to be made."

"Okay, that makes sense."

"But of course, carrying something like that into a fight simply isn't possible. I'll continue to iterate on the original mobile version as well to increase your instant transmission ability. What it will allow us to do is have our allies visit without needing to worry about the existing stability limit."

"You're just doing this so Venelana can come over and help you out without needing the gun," you snipe.

She shrugs, "Guilty as charged."

"And do you have any more plans for mantles?"

"Hm. Not at the moment. Idea generation is the easiest part of the process, Issei's lost scale provides us with a supernatural power that can be applied to other mantle concepts. Defensive and support functions are under consideration to harmonise with Boost's raw power. I suspect that some of your wives may lead us down a path of other 'tribute' acts."

You almost forgot that your 'son' from the future showed up a few days ago. There's so much crazy stuff happening that it doesn't even seem so absurd anymore. Who else could provide inspiration for a new armoured form? You doubt that the Major is going to leak any information about military power armour to you. Girlfriend or not – she takes her job very seriously.

And it does make you wonder about the potential consequences. What if it triggered a serious arms race between governments and militaries to match your own weapons? What if that information got out somehow and caused a sudden jump in military capabilities for one nation? It could very well destabilise the world and cause war to break out. Why the hell are you getting worked up about this again? Mitsuru will come up with something. She always does.

Mitsuru glances back up at you, "You don't need to **** yourself into something, by the way. I know I said that the fate of the world is at stake, but I don't expect you to do as I ask just because of that. As we are now, we can beat them – I'm just worried that things might change."

"Yeah, I get it."

She feels like she's gone a step too far in saying all that stuff about being a devil to you. You understand her logic perfectly well, but this isn't a decision rooted in logic. A younger version of yourself would have jumped at the chance to live out a sexually charged DxD fantasy and become a devil, but now you can only worry about the potential consequences. The curse of becoming an adult.

At the very least, you'll need to have a chat with Rias first. She's the one who holds the evil piece you're discussing. She might have something to say on the matter that Mitsuru might not have considered. And what a coincidence, your phone is vibrating with a message from that very same devil; she wants to know if you can meet at the mansion in a few days when the big work is done.

"Oh, and the rest of your paycheque should be coming through soon," Mitsuru reveals, "Venelana helped me make our... distribution scheme more effective."

A sigh escapes your nose as you slump down onto the workbench, "You mean tax evasion?"

"No. Just obscuring where it comes from and who it goes to; it's just money laundering! Tax evasion is a scourge upon civilised society, you know."

Sometimes you struggle to understand where the line is for this woman.

Wherever it's convenient, it seems.