Free as a bird, in love with a cat

He was Rias' twin brother that disappeared into the world in order to gain what he couldn't in the Underworld. More than half a decade later he returned to help her and others with the current situations that have appeared surrounding Kuoh and Rias herself.

~Chaper 1~

-Underworld-

Located in a hospital in the Underworld the groans of a woman could be heard.

''Keep going dear, you're doing an amazing job.'' The voice of one Zeoticus Gremory could be heard as he tried to calm his wife who was giving birth.

Outside of the room one Sirzechs Lucifer, formerly Gremory and current Satan of the Underworld was nervously pacing back and forth. Sirzechs looked like a handsome young man with shoulder length crimson hair and green blue eyes.

''Sirzechs-sama, please calm down, everything will be alright.'' Spoke a female voice. The voice belonged to a beautiful silver haired, silver eyed woman who was currently dressed in a maids outfit. This was Grayfia Lucifuge, wife of Sirzechs and his Queen in his peerage. She's known throughout the Underworld as strongest Queen due to being on par with the current 4 Satans.

''I know i know, it's just that i'm worried you know?'' Spoke Sirzechs to her.

Grayfia just nodded as she could feel the nervousness rolling of off him in waves and walked up to him and put her hand into his in an attempt to reduce some of his nervousness.

Suddenly the door opened and out came a doctor who bowed slightly towards Sirzechs before he spoke up. ''Sirzechs-sama, Grayfia-sama the delivery went successful and without any problems, if you want you may come in and see for yourself.'' The doctor finished as he stood to the side to give the two a chance to see it themselves

As both Sirzechs and Grayfia made their way inside they came upon a surprising sight.

There laying on one of the hospital beds was his mother and Grayfia's mother in law with not one but 2 little bundles in her arms.

Sirzechs noted that one of the two had crimson hair like himself and his father while the other one's hair took more after his mother Venelana though it had a tad bit of crimson mixed in it aswell.

''Twins!'' Exclaimed Sirzechs in shock at seeing the two babies. For Devils to get pregnant was already a rare occurrence let alone twins.

''Indeed, we were surprised as well.'' Said Zeoticus as they looked to the left of them and saw him look at Venelana and the twins with a smile on his face before he calmly made his way over to her.

Sirzechs couldn't help but smile as well, he now had 2 sibling he could spoil when they grew older and he could-. He was brought out of his thoughts as his wife asked both Venelana and Zeoticus a question he was curious too as well.

''Lord Gremory, Lady Gremory, what are they called?'' Grayfia asked with respect.

Venelana smiled at her before slowly raising her left arm. ''This one we've decided to call Naruto.'' Venelana said as both Sirzechs and Grayfia looked towards the now identified boy with his interesting hair who was asleep.

''This one'' Venelana said after raising her other arm. ''We decided to call her Rias'' As they looked at the little girl with crimson hair on her head who, like the other was also sleeping.

''They're absolutely adorable!'' Sirzechs exclaimed as he watched the two babies who were currently sleeping.

Both parents smiled at their oldest who, despite being the current Satan and being well over 400 years old still acted like a child towards certain things.

''Tou-sama, Kaa-sama, which of the two is the oldest?'' Sirzechs asked them.

At this both parents were quiet for a second as a frown marred their faces, it was well knowns that with twins the oldest even if it was just a minute would become the heir of the family. Unless something else would happen that would make them change heirs such as if Naruto would beat her in combat or such.

''Rias-chan here was the first of the two to be born, though just because she's the heir doesn't mean we won't give them the same amount of love.'' Zeoticus spoke, though everyone caught the meaning of his last words. He basically said that they wouldn't favour one over the other be it either training, teaching or love which counted for everyone.

Not either Sirzechs nor Grayfia would ever do something like that though it was still thrown out.

It was silent for a while as everyone observed the two before Sirzechs broke it with a question. ''When will you two and the babies be allowed to return?''

Zeoticus stroked his chin for a bit before replying. ''Hmm, the doctor said they would run a few test just incase something wasn't completely right but afterwards we could leave.'' He said with the others nodding before Sirzechs and Grayfia left their parents and in-laws with their newborns.

-X- Timeskip 10 Years -X-

Ten years had passed since birth of the Gremory twins and much had happened.

Both Naruto and Rias grew in more ways than just height in the few years they had been alive.

Over the years Naruto's hair grew longer, turning into the same shade of brown his mother had while the tips were crimson like his father, brother and sister. His eyes were a mix between purple and blue unlike the blue green his sister and elder brother had. All in all he took more after his mother much to her happiness as both her other siblings were copies of her husband beside the fact that Rias was female. His personality was more serious than his Sister, while she enjoyed watching Anime he would usually train or read, it wasn't that he didn't enjoy it he just had other preferences.

That didn't stop him for joining Rias when she asked him too, much to her happiness.

When it came time for the parents to tell Naruto that Rias was the heir to the Gremory family Naruto had surprisingly shrugged his shoulders with indifference before congratulating her, shocking those present as they thought he would've gave an different reaction.

When asked why Naruto merely replied that he prefered freedom over the tasks that were usually required of an Heir and didn't like that sometime certain arrangements were made for said person, making his parents and brother flinch a little which he ignored. They were impressed by how much older he acted to which he just smiled in return before continuing with whatever he was doing.

One of the most important things that had happened was when Naruto had shown he had inherited the Bael's Power of Destruction, much to the happiness and joy of his family and even Zekram Bael, who is the First head of the Bael family who is said to have an either greater influence than the current Satans had congratulated his parents after he unlocked his family's power.

-X- Flashback -X-

A seven year old Naruto could be seen standing in the backyard of the Gremory mansion. Opposite of him was his older brother Sirzechs who looked at him with a smile. ''Alright Naruto-kun, we're going to play a little game to increase your reflexes in battle.'' Sirzechs spoke to him as he grabbed multiple baseballs in his hands and began to throw them at him, slowly increasing the speed as time went on.

Naruto was doing his best in trying to dodge them as they came flying at him. Eventually Naruto narrowly dodged one before his senses alerted him of incoming danger as he turned his head and saw one of the balls heading straight for his face. Not wanting to let it his his face he panicked and swiped his hand in front of his face trying to deflect it. What he didn't expect and neither did Sirzechs, was for his body to gain an coat of red energy before it traveled towards his arm, then his hand where it flew outwards, decimate the ball midair.

Seeing this Naruto stopped what he was doing as he was shocked before looking at Sirzechs who looked proudly at him.

Naruto, not knowing what to do charged of his magic out of his body as the power output increased and thickened around him, shocking Sirzechs at the amount of magic he had and the potency of it at his age. All the sudden it stopped as Naruto was tired before little by little the aura disappeared and he fell unconscious. Just before he reached the ground, Sirzechs, in a show of speed appeared behind him, catching him while looking at him with a proud smile before picking him up and brought him back inside for him to relax.

-X- End Flashback -X-

Naruto still remembered that day how he woke up after his slumber as his parents congratulated him and how they were proud of him. Even Rias, his sister did though she did glare at him cutely in jealousy making him smile at her.

Little over a year after Rias too showed signs at having inherited Bael Clans Power of Destruction, though they noted hers magic pool wasn't as big as his it was still above the average Pure-Blooded Devil.

Currently Naruto was in the living room reading one of the many books his family had before he was interrupted by Rias who barged in, startling him much to her joy.

Rias' crimson hair grew longer, reaching her middle back. Like her brother she too had an ahoge, reminiscent of her brother and mother, her green/blue eyes had mirth in them as she looked at him with a smile on her face.

''Yes Rias-chan?'' Naruto asked her sister who was still looking at him.

''Nii-kun, Nii-sama is asking me to get you as he will bring us to Ajuka-sama to get us each an Evil Piece set.'' Rias spoke.

Naruto raised an eyebrow but on the inside he was excited. The Evil Pieces were a genius creation by Ajuka Beelzebub as a way to increase their numbers after the war. A Pure-Blooded or High Class Devil were the only eligible for a set which was based after Chess making it a have to for any High-Class Devil.

''Very well, let's get going then.'' Naruto spoke before he closed his book and stood up and walked over to her. Currently Naruto was an inch or 2 taller than Rias who stood at 4Ft 6. Together they walked to the front were they saw their brother waiting for them with a smile on his face.

Sirzechs absolutely adorned his two siblings and it was widely known throughout the Underworld that he would do anything for them should either of the two ask.

''Naru-tan, Rias-tan are you ready?'' He asked childishly, making both nod at him. ''Very well just keep close to me alright?'' Sirzechs spoke before they walked off to one of Sirzechs friends.

-X- Ajuka's Lab -X-

As they arrived both Naruto and Rias took notice of the creepy feeling they had which increased as they went closer. Arriving at the door Sirzechs knocked twice before they heard a click as Sirzechs held the door open, letting Naruto and Rias enter first before following behind them. Sirzechs stopped in the middle of the hallway before he suddenly spoke. ''Ajuka, Naruto-kun and Rias-chan are here to collect their Evil Pieces.'' Sirzechs spoke to seemingly no-one.

Before either Naruto or Rias could question him the door to the elevator opened up prompting them to enter.

As they entered they saw Ajuka looking at them standing next to one of the many machines in the room. Ajuka is a handsome man with green slicked back hair who had an aura around him that Naruto couldn't really determine what sort it was.

''So,'' Ajuka spoke. ''It's time for Naruto and Rias to receive their Evil Piece Set you say, huh?'' The last was said gazing towards the two kids who nodded their heads and had smiles on their face.

''Very well, who's first?'' Ajuka asked.

Naruto and Rias looked at each other before nodding as Rias stepped forward indicating she went first.

''Rias will go first i see.'' Ajuka said as he led her toward the machine. As they arrived Ajuka brought her to the machine before typing in certain commands

A few seconds later the machine began to work as a chess set came out of it. Grabbing the set Ajuka walked towards a table with Rias following him before putting the set down.

''Now, Rias i want you to drop a bit of blood onto the pieces to link each and everyone of them to you.'' Ajuka said.

Rias did what she was told as she made a shallow cut of her fingers, letting a few drops of blood hit the chess pieces. Once she was done a red glow covered them, causing her to shield her eyes before it disappeared showing that each of her pieces gained a crimson color, the same as her hair.

Inspecting them with childlike wonder Rias saw that one of her pieces, a Bishop looked strange. ''Uhm, what is with this piece? It looks strange.'' Rias asked causing everyone to look at it to see it indeed had a strange appearance, making Ajuka rub his chin.

''Hm, it seems one of them changed into a Mutated Piece. Mutated Pieces are rare occurrences that can happen during the transformation process and are more powerful than their regular counterpart so congratulations on that.'' Ajuka explained making her smile.

''Now Rias, please come her and synchronise with your set to ensure there will be connection with the Pieces in the future.'' Ajuka told her. Rias did as she was told and followed Ajuka towards a Machine were the process began. Seeing everything was done Rias thanked him before walking towards Sirzechs who smiled at her before inspecting the Pieces.

''Now it's your turn Naruto-kun.'' Ajuka said getting him to nod and walk forward. Replaying the actions Ajuka put his set on the table before giving him space. Naruto looked at them before grabbing the knife and cutting it across his hand without batting an eye, making Rias flinch at seeing him doing it so casually.

Letting the blood freely fall on his pieces they, like with Rias gained a glow themselves though it was a darker shade of red. Once it disappeared they all looked and saw them being a mix between black and red. Like Rias, Naruto too had an strange looking Piece which he grabbed to inspect.

''Amazing it seems that like Rias you too got an Mutated Piece, Naruto-kun. Though yours is a Queen instead of Bishop.'' Ajuka informed him, making him nod in understanding. After that Naruto grabbed his Evil Piece Set before he repeated what Rias did as the Piece entered him. For a second his body was surrounded by a crimson glow which was caught by only Sirzechs and Ajuka but kept silent about it.

Clenching his fist at the feeling of its power Naruto turned to Ajuka before bowing slightly and thanked him as he made his way back towards Sirzechs.

''Well it seems we're done here Ajuka, thank you for your time and i speak to you later.'' Ajuka spoke towards him who gave a subtle nod in return as he watched Sirzechs walk off with his two siblings.

-X- 2Timeskip -X-

Two years had passed since both Rias and Naruto received their Evil Piece Set.

Naruto had grown to 5 ft 4 making him quite tall for his age, his hair grew out aswell and ended just above his shoulder which fit him better. Constant training improved his body and already large magic pool making him an eye catch for girls around his age much to his annoyance and his family's enjoyment watching him struggle.

Rias on the other hand only grew a little making her pout whenever Naruto would tease her for her height. She had let her hair grow out which now went just passed her back. Unlike Naruto who spent most of his time training she wasted it on Manga and Anime.

There were some less than happy events that had occurred that surrounding Rias, one of those were about a Marriage between heir of the Phoenix family and her, the heiress of the Gremory.

He remembered the glare she sent her parents and brother, making them all flinch in sadness at seeing her like thought they were doing her a favor but Rias was vehemently against it, claiming that she wanted to choose her own future, something he agreed with if his brief spike of power was any indication. Afterwards Rias ran off to hide in her room, letting no one except him inside who tried to calm her the best he could. It was ultimately solved after both he and Rias watched a marathon of Anime with him holding her. The day afterwards life went back to how it used to much to his parents relief.

Naruto on the other hand also had numerous offers for marriage all which he declined telling his parents that he wasn't the Heir and would choose whoever he would fall in love with which they accepted much to his relief.

One of the many request for a marriage was the Sitri family, knows for their Water-Based Magic between their Heiress Sona and himself. Sona who was and young girl with short bob-cut dark hair and violet eyes combined with glasses. Sona was a girl who enjoyed strategy based games evident by the amount of chess she played.

While Sona and Rias got along great the same couldn't be said for Naruto. One of the reasons was because Sona had more or less a crush on him which was one of the reasons her family had offered a marriage contract. So when he denied it she took it quite personal gaining Naruto the wrath of her elder sister, Serafall Leviathan, a beautiful woman with black hair like Sona except longer and done in twintails and violet eyes like her sister, who one midday walked up to him during training, grabbed him and demanded why he denied 'her Sona-tan's hand in marriage.' while shaking him and aiming quite a large amount of KI at him.

Luckily this was stopped due to Sirzechs interference, which calmed her down much to his relief. Afterwards Naruto had a meeting with both Serafall, Sona and the rest of her family where he explained that he was too young to be bound to something such as a marriage contract and told them that if he would fall for her normally he wouldn't mind but disliked the idea of being stuck to a contract for either of them and that if he were to fall in love with someone else he would have wasted both their time with the false hope of marriage.

Hearing his answer they all smiled at him, even Serafall and commented on how much older he sounded with the reasons he gave and agreed that they could not do that to either of them.

After that Naruto was slightly cautious what he said to Sona, not willing to relive what happened with her elder sister again, while Sona still had the occasional blush around him.

Other than that the only noteworthy thing that happened was that his sister gained her first Peerage member, Akeno Himejima, Rias' Queen.

Akeno Himejima was a dark haired girl the same age as Rias, Sona and himself. She too had violet eyes though not to be confused by those of the Sitri Clan.

Akeno Himejima, who Rias, together with her father's Bishop had saved from dead after she was kicked out and chased by Himejima Clan members due to her Fallen blood. When asked about her parents Akeno replied that her mother was Shuri Himejima, a miko priestess while her father she spat out the word father like venom was none other than Cadre level Fallen Angel Baraqiel. Hearing she had no place to call home Rias had quickly offered her a place in her Peerage, promising her a home and that her family would take care of her. Seeing to deceit Akeno accepted her offer, eventually becoming her Queen and best friend along with Sona.

Her and Naruto got along quite well much to Rias' joy as she couldn't bare having her Queen and brother disliking the other.

Naruto on the other hand hadn't used a single Piece of his set. When asked he would simply replied he hadn't found someone special enough before dropping the subject completely.

Currently Naruto was in his room thinking over a decision that would be utmost important. He wanted to explore and see more of the world, not the Underworld but Earth, where regular humans live ignorant of the existence of Devils, Fallen or Angels. Deciding he needed advice Naruto went looking for his elder brother who should be somewhere in the mansion.

After walking around and searching for him Naruto finally found Sirzechs sitting in his office behind his desk. Knocking twice before entering Sirzechs looked up to him as he walked in before he took a seat in front of him and stared.

Seeing Naruto staring of him Sirzechs returned it before eventually breaking the contest and began to ask what he was here for.

Still staring at him Naruto took a deep breath before opening his mouth and said. ''I want to leave.''

Sirzechs was shocked, leave? What did he mean by that?

''Umm Naruto-kun, what do you mean you want to leave?'' Sirzechs asked him hoping he wouldn't say what he thought he would.

Naruto sighed before he ran his hand through his hair and spoke up. ''I want to explore the world, not the Underworld but the world itself, i want to talk with regular humans, to see what they're like. I want to travel different countries to see what it's like, to understand how the world works and gain experience. I want to look for members for my Peerage that i can't find here.'' Naruto said as he licked his lips before continuing. ''But most importantly i want to be free, free from my current lifestyle, free from my concerns i have here and just live how i want to.'' Naruto finished while looking his brother in the eye.

Sirzechs, while shocked showed nothing as he looked back into his eyes, inwardly he was proud of him after hearing the boy's speech. The boy wanted to gain something he couldn't get here though he did wonder about something.

''Naruto, why are you telling me this and not Kaa-sama or Tou-sama?'' Sirzechs asked Naruto.

''Well, there's no way they would ever let me out myself, i mean i'm their child they would worry over me like any parent would. Now, you on the other hand are a bit more neutral, you know? Yes, you care about me and Rias' wellbeing more than an normal person would but you know i can take care of myself and while Father and Mother do as well they won't admit it and say i'm too young.''

''Alright.'' Spoke Sirzechs.

''Eh!'' Naruto exclaimed out of shock. ''You're serious?'' Naruto asked.

''Alright.'' Sirzechs repeated. ''I agree that exploring the world is good for you and would gain you more experience than you could get while staying in the underworld… However, you WILL contact me immediately should there be anything that you're unable to handle, non negotiable.'' Said Sirzechs as he handed him a paper that would summon him should the need arise.

Naruto stood up in happiness as he hugged Sirzechs with all his might who hugged him in return. ''I'll inform our parents and Rias. You do know Rias will be devastated right?'' Sirzechs asked Naruto who sadly nodded his head.

''I know it's just… tell her that i apologize for not telling this herself but that i need this in order to grow. Also tell her that i will be there should it happen, she knows what i mean.'' Naruto said.

''Very well, goodbye.. otouto.'' Sirzechs spoke with sadness

''Goodbye as well, Nii-san, and once again i'm sorry for Rias' reaction.'' Naruto said before he hugged him one more time and left.

Neither knew that they wouldn't see the other for little more than half a decade.

~Chapter 1 End~

Just had a new idea and wrote this from it.

As you saw it's Naruto x Kuroka, why? Because i like her character.

For Rias i'll probably go with Canon pairing mainly due to there not being a whole lot of options..

Anyway, hope you enjoyed this chapter, leave a review for any suggestions so i might implement them in to this story.