I know, I did it again, another story… I need to stop, but I just get too many good ideas. I was on the bus to Uni and thinking of how to get Serafall with Issei in Heart of a Dragon, then lamented the fact that Grayfia can pretty much never be with Issei, then, it a twist of luck, I had been working through my backlog of new chapters (seriously, I have had no time to read and still have about 40+ chapters to get through) and happened to read the latest chapter of The destroyer of heaven, which helped spark the gears in my mind. By the time I had come home, I had most of the background settled, I just needed to come up with my main plot point. Flashback to Serafall and Grayfia and ta-da, my idea was born: Issei Leviathan.

To start off, Issei will be very OOC in the first chapter, but eventually he will start to show more of his canon traits, due to reasons I won't explain yet, as they give away a part of the story.

If you didn't realise, this will obviously have Issei/Serafall/Grayfia… but there is also another person who I was struggling to put in both my other DxD stories… who just so happens to fit nicely into the plot for this one… so the lucky third addition will be: Rossweisse.

However, I can't think of anyone else for Issei's harem right now, especially since he has set the bar really high and whoever he gets with needs to be really, really strong, once again, for reasons I won't explain yet, as they give away a part of the story.

Although, I bet none of you expected me to ever do a Issei-devil story, since some of you have decided I am set against devils and a Rias-hater… which isn't true, looking at you A Man's Heart reviewers who jump to conclusions at chapter 2. Seriously, you guys need to trust me more on my stories. I can tell you everything that happens and why, but then why would you read the story?

Well, that's all I really have to say for now, so enjoy the chapter and let me know what you think.
SSJ3 Kyuubi Gohan.

Disclaimer – I don't own anything from the High School DxD anime/manga/light novel. All I own are my original characters and plot twists.

'Talking'

"Thinking"

'Ddraig talking and Sacred Gear sounds'

"Ddraig thinking"

*expression*

Flashback

Chapter 1 – Leviathan

'Even if I have to sacrifice my life, to take one of the three faction leaders down, that is a worthy trade.' Said Katerea Leviathan, a busty bespectacled woman.

'Hmm, that isn't an equal trade to me.' Commented Azazel, leader of the fallen angels as he examined his left arm, wrapped up in Katerea's suicide attack.

As Azazel, clad in the armour of the Sacred Gear he had created, Downfall Dragon Spear, prepared to cut his arm off, the multitude of arms that burst from Katerea's form were suddenly severed, by a jet of water.

'Shame on you Katerea. A Leviathan does not commit suicide. A victory is not a victory if you are not there to witness it.' Said a deep, rumbling, baritone voice.

The two combatants turned to face the person who had interrupted their battle and both were noticeably shocked.

'Issei? What is the meaning of this?' Asked Azazel curiously.

'Oh, Governor of the Fallen, it has been some time.' Commented Issei conversationally.

'What the hell do you think you are doing?' Shouted Katerea in rage.

'Know your place Katerea, you are much too young to mouth off to your own grandfather.' Said Issei coldly, getting a confused look from Azazel.

'Issei, are you feeling alright?' Questioned Azazel curiously.

'Of course, although, I suppose my awakening was rather sudden, I believe this should prove to be sufficient evidence to support my claim.' Said Issei, before twelve devil wings burst from his back and his power skyrocketed.

Everyone in the vicinity, mage, devil, and angel, turned to look at Issei in shock.

'This pressure… I have not felt anything like this for decades.' Commented Azazel in shock.

'Yes, the cycle of reincarnation is rather tenuous to grasp. I suppose being the original serpent would cause some delays, especially with my indomitable will and desires.' Said Issei calmly, before turning to Katerea again.

'Now, cease this foolishness. A Leviathan willing to give their life, merely to reclaim the underworld… how low has my name sunk since my death, that my descendants would be reduced to cannon fodder? I will change this from now on though. In the meantime, you will listen to me now, understand granddaughter.' Said Issei, focusing his energy on his descendant.

'O-of course.' Stuttered Katerea fearfully, before Issei let up his pressure.

'Good, with that out of the way.' Said Issei, before swiping his hand, causing all the invading mages to explode in a shower of gore, as their blood vessels haemorrhaged.

The gathered powers looked on in shock, barring Azazel and Michael, who had seen such power before.

Issei swiftly descended to the ground, shortly after which, Azazel joined him, keeping a fair distance from him, while Katerea ungracefully touched down.

'Hmph, embarrassing.' Scoffed Issei, before some of his energy burst towards Katerea and restored her clothes, while also revitalising her partially.

Rias hesitantly approached Issei, unsure of what was wrong with him.

'Issei, are you okay?' Asked Rias tentatively, as Issei turned his gaze on her.

'Ah, the Gremory princess who helped me regain my status as a devil. Thank you for the role you played in my awakening, but, I am afraid that I am no longer to serve under you.' Said Issei, before eight red chess pieces appeared in his hand.

Those gathered looked at him in shock.

'Issei! What did you do?' Asked Rias in shock, hand clasped to her mouth in worry.

'I do apologise, but a king such as I, will not bow to anyone, nothing personal of course.' Said Issei, as he walked up to Rias and dropped his pieces in front of her, which she quickly caught from falling to the floor.

Issei then walked over to Serafall Leviathan, the current Leviathan, and gave her a scrutinising glance.

'A Leviathan who utilises Ice magic… how peculiar… although, it is still a domain of water, so I suppose it fits. I will come by and test you some time, to ensure you are not soiling my name as well.' Said Issei, sparing a quick glance to Katerea, who flinched under his gaze.

'Issei, is there something you wish to tell us?' Questioned Sirzechs.

Issei looked at the crimson Satan, before looking past him, into the eyes of the Silver Haired Queen of Annihilation.

'You are the daughter of Lucifuge, are you not?' Questioned Issei rhetorically.

Grayfia looked at Issei in surprise, before a magic circle appeared around Issei's hands. Issei snapped his fingers causing the circle to shatter and instantaneously, Grayfia felt a chill run down her spine.

'You are, and it seems Lucifer's deal has been upheld… that devil always did keep his word to me in the end.' Commented Issei, with a small smirk.

Everyone's attention was suddenly brought to Azazel, when an attack was launched at him… by none other than his charge, Vali, the White Dragon Emperor.

'Ah, I was wondering when you would try something, Vali.' Said Azazel calmly, as he climbed out of the hole he had just been blasted into.

'Well, I would have done it differently, but now seemed like the right time.' Commented Vali, clad in his white armour.

Vali glared at Issei from under his mask.

'I suggest you not bite off more than you can chew, young Lucifer. Even your ancestor took me completely seriously when we sparred.' Said Issei dangerously, getting a few gasps of surprise.

'So, this isn't just some act, Issei… how surprising, for the two wielders of the Heavenly Dragons to be descendants of the original Satan.' Commented Vali.

'I am actually a reincarnation.' Stated Issei simply.

'All the same, I am now even more excited that you are to be my rival. A devil, and the holder of the Boosted Gear, how ironic.' Said Vali.

'Rival? I'm sorry to disappoint you, Vali, but you are just simply not a concern of mine anymore.' Dismissed Issei, causing the younger members gathered to look at Issei in shock.

'Really? You're ignoring me?' Questioned Vali, with a hint of steel in his tone.

'Nothing personal of course, but I have much, much more important things to deal with.' Said Issei calmly.

'And what is it that you wish to accomplish, Issei?' Questioned Michael.

'The same thing I wished to do before it was stolen from me by your creator.' Said Issei, glaring at the archangel.

'What could that be?' Asked Azazel curiously.

'Why should I tell any of you anything? There are only three people here I care about right now, my direct descendant, the one using my title and the one from Lucifuge.' Retorted Issei.

'Mou, can't you tell us, pretty please Mr. Leviathan?' Asked Serafall curiously.

Those gathered looked at her in shock, at how casually she was speaking to, if his words were to be believed, the original Leviathan.

'Hmm, well… since it is you asking… very well.' Said Issei, getting a few to look at him in thinly veiled disbelief.

'Michael, Azazel, I don't suppose either of you remember why the Satans fought against God?' Queried Issei, only to receive two negative responses.

'Well, Beelzebub and Asmodeus were merely sheep. They fought in the war because Lucifer and I did.' Said Issei, surprising a few of the devils.

'You see, the reason we fought was simple. While our reasons were the same, the motivations behind them were different. Lucifer fought to get revenge for being cast out of heaven, I'm sure you remember that, Michael.' Said Issei, getting a nod, from the angel who had cast out Lucifer.

'I too sought revenge against God, but not for any reason such as anger or indignation, no, I sought revenge for having my life's purpose taken away from me.' Said Issei, with a hint of anger in his tone.

'What would that be?' Asked Sirzechs curiously.

'I will not say, it is something wholly personal to me and me alone, although, given how we struggled to defeat God, I would have no doubt failed in my task. I believe, that for this reason, I have been wavering through the cycle of reincarnation. My dying will kept me from doing so prior, I believe, due to the single desire I possessed before my death: that of power. I needed more power, and in this vessel, I am the wielder of the Heavenly Dragon Ddraig. For that reason, my will merged, with Issei Hyoudou… although, I suppose now, it is more appropriate to call me Issei Leviathan. My conscious will, having merged with Hyoudou, has now led to my new self. I am not truly the original Leviathan, as I am human to some extent and also dragon, having given up my left arm, but I am not a simple reincarnated devil anymore either, I have the memories and powers of the true Leviathan.' Said Issei calmly.

The brief silence was then shattered, as a new figure, wearing Chinese armour appeared.

'Vali, time to go.' Said Bikou, a descendant of the legendary Son Goku.

'Hmph, very well, but know this, Issei, we will have our fight.' Declared Vali, before he left with the new arrival.

'Hmm, I am surrounded by petulant children it seems.' Grunted Issei.

'So what do you plan to do now? Are you to reclaim the seat of Leviathan?' Asked Sirzechs curiously.

Issei looked over to Sirzechs, before glancing at Serafall and walking over to her. Serafall, to her credit, didn't flinch, and merely stared down the Leviathan. The stare off lasted well over a minute, causing tensions to rise among the group, before Issei suddenly smirked.

'No, I believe not. I think you forget, Leviathan is a title to all of you, but I am the original Leviathan and no one can take that from me… besides, I believe Serafall here will in fact become a true Leviathan.' Commented Issei.

'What do you mean, I am a true Leviathan.' Pouted Serafall, getting most gathered to look at her in exasperation and Katerea to grit her teeth.

Issei leaned in closer, until he was only a hairs breadth away from Serafall's face.

'Not yet my dear, but you will be. You will be mine.' Whispered Issei teasingly, into Serafall's right ear, getting chills to run down her spine.

'Also, Lucifuge, I believe you must not know, however, I'm sure you wondered why you could never feel an attraction to any devil before.' Said Issei, as he stood up and looked at the maid.

Grayfia's eyes widened, as she quickly pieced together the facts available to her and looked at Issei searchingly.

'Indeed, Lucifer and I were good friends and each offered a trade of sorts with each other. Although we usually saw eye-to-eye, in order to ensure we both had full support behind each other, we made a trade of sorts. I will not say what I gave and I won't say what I was promised, but I'm sure you are smart enough to gather from context, servant to the house of Lucifer… the original Lucifer, mind you.' Said Issei, confirming Grayfia's suspicions.

'Now, I will be off, I need to take care of some business, but I will come by to the Underworld soon and announce my presence. Of course, with one of the original Satan back, I do believe that many of those discontent with your current government, will fall in line, especially once I complete all my arrangements… and then some.' Said Issei, sparing a smirk at the confused Serafall.

'Now, come Katerea, there is much to be done!' Ordered Issei, causing his descendant to quickly rush to his side, before a large magic circle with the symbol for Leviathan appeared under the two.

'Oh, and just as an aside, I'll throw in my vote for peace. After all, it will help me achieve my life's ambition.' Said Issei, before he and Katerea disappeared.

The younger devils all released a heavy sigh once Issei left, as he had not stopped exuding his power, making it difficult for them to breathe and move.

'Well, I must say, this meeting did not go at all the way I expected it too.' Commented Azazel.

'That's putting it mildly. To think, one of the original Satan would come back, reincarnated in the form of Issei Hyoudou, holder of the Boosted Gear.' Added Michael.

'Well, in any case, I do believe we achieved what we set out to achieve in this meeting, that of peace between the three factions. It also appears that Issei will in fact bring back some of the dissenters of the Old Satan faction as well, which is immensely beneficial for us, devils in particular, as it will reduce the chance of a civil war immensely.' Said Sirzechs.

'Although, I do wonder what he wants from Serafall and Grayfia.' Said Azazel curiously.

'I believe I know what he wants from me.' Said Grayfia, sending a pointed glance at Sirzechs.

'Well, we both knew the charade was dated.' Conceded Sirzechs, with a nod to Grayfia, confusing those around them.

'What charade?' Asked Azazel curiously.

'That is personal.' Said Grayfia coldly.

'I see.' Said Azazel, with a knowing smirk.

-line break-

The two Leviathan appeared in a dark forest.

'Now Katerea, explain to me why my line has become so weak?' Questioned Issei, glaring at his descendant.

'What do you mean, your line is as strong as ever, the line of Leviathan?' Protested Katerea nervously.

'Is that why my most defining ability is not used by my descendant?' Asked Issei, raising an eyebrow questioningly.

Katerea looked at Issei in confusion, before a spear of sharpened water came dangerously close to her left eye, flowing rapidly back and forth in place, maintaining its shape.

'The Leviathan was the serpent with dominion over water, yet I did not see you use it against Azazel at all. Do you not understand the power of the Leviathan? Have you forgotten why my name was feared? My name wasn't feared because of a meaningless title, it was because the battlefields I fought on were awash with blood. Even the Sitri clan, those known to specialise in water-based magic, were nothing compared to me… so why, has my descendant become weak?' Questioned Issei.

'That new Leviathan is a Sitri! So I set out to defeat her without my own magical prowess!' Growled Katerea.

'Pride? You are not a Lucifer, Katerea. I know the truth so don't deny it.' Said Issei commandingly.

'Fine! It was because she took what should have been mine! I am the true Leviathan, not that childish girl!' Shouted Katerea in frustration.

'If you had acknowledged the truth, you wouldn't have been in this mess. A true Leviathan draws power from their envy. Denying it, along with your true powers, is why you are weak, which we will soon rectify.' Said Issei, before starting to walk deeper into the forest, expecting his descendant to follow after him.

As the duo waded deeper into the forest, Katerea started to notice her surroundings.

'Why did you bring us to the Forest of Familiars?' Asked Katerea curiously.

'Good, you noticed.' Said Issei approvingly.

'Well, to answer your question, I am here to regain my old friend, one who has been with me since the beginning.' Said Issei calmly.

Issei continued walking until he reached a large cave, with water flowing around it, forming a shallow pool in the centre. Issei stepped into the pool and waited, telling Katerea to wait on land.

A deep rumbling sound was heard and seemed to be approaching Issei, who stood there unmoved. Eventually, when the sound of stamping claws slamming against the ground became deafening, a vicious looking scaled head, not too dissimilar from a dragon head, emerged… quickly followed by eight more. Two thick webbed wings came into sight along with a heavily spined, scaly body.

Katerea felt her blood run cold, as the Nine-Headed Hydra was finally revealed. She unconsciously backed up a step, before looking on in shock, when the creature brought its head towards Issei in a small bow, who then patted the creature on one of its many heads.

'It is good to see you once again, old friend.' Said Issei fondly.

Katerea finally managed to overcome her shock and speak.

'Old friend? The Nine-Headed Hydra is one of the most evil familiars, one who would even kill its own master.' Said Katerea fearfully.

'Of course, for there has and always will be, only one master that the Nine-Headed Hydra would bow to. A true Leviathan of course. If you were a true Leviathan, you would not fear one of my most trusted comrades during my life. If you were a true Leviathan, even he would bow to you.' Said Issei.

The Hydra looked at Katerea, before exhaling in a manner, which Katerea identified, as contempt.

'It appears that Umimaru does not recognise you as a true Leviathan.' Commented Issei, continuing to pat a head of the Hydra.

'Umimaru? What kind of a name is that?' Asked Katerea, with a huff, only to freeze when she heard nine growls.

'Umi, for he has dominion over the sea. The Nine-Headed Hydra has no equal in the water. The Leviathan should also have mastery of water, Katerea.' Chided Issei, before turning back to Umimaru.

'Will you serve with me once again, old friend?' Requested Issei.

The Hydra gurgled, in what Katerea assumed, was contentment.

'Thank you, I will be sure to bring you a treat next time.' Said Issei, before a magic circle with the symbol of Leviathan glowed under the Hydra, bathing it in a pale glow, before fading.

Issei stepped away from the serpent, causing it to let out a small grunt of unhappiness, before turning around and retreating back into its cave.

'Now then, tell me what has become of the house of Leviathan?' Demanded Issei.

'Most perished in the civil war...' Informed Katerea hesitantly.

Issei's eyes hardened at this, causing Katerea to flinch.

'Are you to tell me, the noble line of Leviathan has nearly become extinct?' Asked Issei dangerously.

Katerea hesitantly nodded, before a wave of immense power burst from Issei, causing her to drop to her knees from the sheer malice coming from the energy. Issei's power eventually receded, allowing Katerea to stand and breathe comfortably again.

'This displeases me greatly… but also pleases my recent reincarnation.' Said Issei calmly.

'What do you mean?' Asked Katerea in confusion.

'Simple, if my line is dying out, I will just start rebuilding it.' Said Issei.

'You mean…' Said Katerea, before trailing off.

'Yes, a harem. Although, my line will be strong, I will not tolerate any weakness in my mates… and I believe I have two in mind already.' Said Issei thoughtfully.

Katerea thought for a moment, before scowling.

'Please tell me… you're not suggesting who I think you are.' Groused Katerea.

'Well, if she wants to use the name of Leviathan, she might as well help bring it back.' Said Issei, with a shrug.

Katerea growled for a second, before chuckling.

'Heh, that would make her my grandmother… that is so not right, but at least I can call her an old hag.' Muttered Katerea, but Issei heard her.

'You do realise you are older than her, right?' Questioned Issei.

'Don't take this from me! If you're going to start sticking it physically to my rival, then I'm sticking it to her verbally!' Shouted Katerea.

'You're acting rather petulant, granddaughter.' Commented Issei, with a small amused smile.

'It is your fault, your presence is changing me and I can't explain why.' Defended Katerea.

'No doubt, due to a lack of any elderly guidance and the chance to be childish. You were merely a suppressed adult before, acting the way you thought you needed to, but now, you are acting the way you really want to.' Explained Issei.

'So you're saying I was just a repressed kid acting like an adult?' Said Katerea, with narrowed eyes.

'More or less, it happened a lot during the war. Parents dying left, right and centre, led to kids trying to emulate them.' Shrugged Issei.

Katerea was silent at this, before Issei started walking towards her.

'Come, I would like to see the state of the Leviathan line now, take me to what remains of it.' Said Issei.

'Ok, but don't explode when you see what the state of it is.' Said Katerea apprehensively.

'If need be, I will just destroy a few mountains.' Said Issei nonchalantly, getting Katerea to sweat-drop, before she formed a magic circle under their feet.

Ok, so there are two things I need to ask really quickly:

First, would you guys mind me using characters from other fandoms? I was thinking of either all, or a subset of: Cobra/Erik and Kinana from Fairy Tail, Orochimaru and Anko from Naruto and Renji from Bleach. Please let me know if you would prefer me to not add characters from other fandoms.
If I do add them, they will become rather significant to the story. If you notice the common theme between them, you'll know why.

Secondly, I have been doing a lot of deliberation and I have contemplated cutting down my harems from my other DxD stories. What this would mean, would be shifting people from, say, Heart of a Dragon, to this one and modifying who is in the harem for A Man's Heart… so my question is; and I will ask this on my other stories as well (half of the next chapter for A Man's Heart is done by the way), but would you prefer for me to cut down my harems a little?

Some ideas I've been thinking of, were moving Rias to the harem for this one, dropping Xenovia from Heart of a Dragon and focusing on her in A Man's Heart instead, possibly shifting Yasaka to this one as opposed to A Man's Heart. Dropping Serafall and Rossweisse from Heart of a Dragon to focus on them more in this. Basically, here is what I am currently thinking of.

HOD: Irina, Akeno, Raynare, Ravel, Kuroka, Xuelan, Karlamine, Ophis.

AMH: Gabriel, Kuroka, Irina, Ravel, Xenovia, Le Fay.
Maybe Akeno and Raynare (I have a few ideas I'm working with).

IL: Serafall, Grayfia, Rossweisse, Tiamat, Rias, Yasaka.

So that's what I'm thinking as of now. I really don't want to use the same people in each harem, so it doesn't get boring, but some I just can't help have in two, such as: Irina, Kuroka and Ravel, as I really like all three quite a bit and they mesh well with Issei, not to mention, I've already developed their relationships to a point in each story, that taking them out would just be stupid.

In any case, any and all feedback is appreciated. The next few updates will be for my Fairy Tail stories, but like I said, I've almost got half of the next chapter for AMH done.
That's all for now and please, PM or review to give me feedback on my two questions.
Thanks.
SSJ3 Kyuubi Gohan.