Disclaimer: I do not own any series in this crossover.

Note: Sense Issei's parents are going to have a bigger role in this story I've got to give them names, since they're never actually given names (as far as I know).

Red Dragon Nephilim

Chapter 1: Issei's Guardians

"Ise," said Sachiko Hyoudou as she stared at the young girl sitting in front of her with a kind smile, "Mitsuru, could the two of you leave me and Rias-san alone for a few minutes?"

Sitting in her chair at the table, Sachiko Hyoudou was a middle-aged woman with long dark brown hair in a ponytail, light brown eyes, and faint but still noticeable wrinkles on her face. She wore a tan short-sleeve button-down shirt, with navy blue pants and white slippers. She was a fulltime housewife, and enjoyed spending time around the house, though occasionally went out for a part-time job.

Sitting next to her was her husband, Mitsuru Hyoudou. He was a middle aged man with spiky light brown hair, dark brown eyes behind a pair of glasses and slightly more noticeable wrinkles than his wife. He wore a striped sky blue short-sleeve button-down shirt, dark grey pants and blue slippers and held a newspaper in his hands. He was an ordinary office worker, who usually came home tired until he'd gotten a taste of his wife's excellent cooking.

Sitting across from Mitsuru was their son Issei Hyoudou, often called 'Ise'. He was an average looking seventeen year old, with spiky brown hair and light brown eyes. He wore his school uniform which consisted of a black blazer, over a white long-sleeve dress up shirt, with black highlights and a black ribbon on the collar, both of which he wore open, revealing his red t-shirt underneath, and black pants. Issei was second-year student at KuohAcademy, with a reputation for being a pervert and an obsession with women's breasts, though if you could get passed that, he was a decent person.

And finally, sitting directly across the table from Sachiko, was Rias Gremory. She was gorgeous, with her long red hair, blue-green eyes, light skin tone, and a buxom figure. She wore her school uniform, consisting of a white long-sleeve, button-down shirt with a black ribbon on her shirt collar worn under a black shoulder cape and a matching button-down corset, a magenta skirt with white accents, and brown dress shoes over white crew-length socks. She was a third-year at Kuoh Academy, and was admired by nearly all of the other students for her beauty and elegance.

At her request Mitsuru and Issei got out of their seats and walked out of the dining room. Rias and Sachiko continued to smile at each other, until Rias started the conversation, "I must say, you are quite the actress, Angel-san." Sachiko sighed, and then closed her eyes as she began to glow brightly. Her wrinkles faded away and vanished as a halo appeared over her head and beautiful white wings grew from her back. She opened her eyes and they had changed to a golden color.

"I should've known that you would've seen through me," said the now revealed Angel, who looked almost twenty years younger than as a human, "I supposed it was pointless to try and pull one over on the princess of the Gremory clan." Rias waved her hand in dismiss, "Oh no, your act was very good," she said complimentarily, "I barely saw through it."

"So Angel-san," Rias said, her expression turning serious, "I take it you wished to speak with me about Issei?" Sachiko's expression changed to serious as well, "That is correct," she replied, "Since you are the one who turned my son into a Devil, I figured it would be best to let you know the truth."

"You don't seem too upset about your son being reincarnated into a Devil," Rias said curiously and Sachiko sighed before replying, "While I was indeed shocked when I first sensed a demonic aura emitting from him, there's no point in complaining about what's already been done," she paused to take a sip of her tea, "though I will admit, I'm worried about how this will affect him in the future, given his status as a Nephilim."

"So you are indeed his birth mother?" Rias inquired before taking a sip from her own tea, "Of course!" Sachiko exclaimed, smiling toothily, "Can't you see the family resemblance?" Rias inwardly chuckled at her quick change in tone, before returning her thoughts to the situation at hand, "If you weren't his birth mother or had you been human, this would be much easier to deal with."

"I was rather surprised when I discovered Issei was a Nephilim," Rias said as she thought back to that brief moment when Issei was being reincarnated, he grew angel wings that vanished the next moment, "though even more shocking is that he was birthed from a pure angel."

"I suppose it would be shocking," Sachiko said with her eyes closed, "considering nephilim are typically born between humans and fallen angels." Rias closed her eyes as she thought about her 'Queen' Akeno Himejima, who was the child of a fallen angel and a human, "true, though it's even more interesting that I was able to reincarnate him into a devil, had he been the child of a fallen angel, I could rationalize this more easily."

"I believe I can explain," Sachiko said as she finished her tea, "I have two theories for why you could reincarnate him into a devil," she then put her cup down, "My first theory is the bugs in God's System. Due to an imbalance of power between Heaven and Hell, the bugs in God's System could be exploited, resulting in a fusion of Holy and Demonic elements."

"My second theory is the seals that have been placed on Issei had limited his Holy aura to the point that your Evil Pieces didn't recognize it." Rias narrowed her eyes at that bit, "Seals?" Sachiko looked at her, slightly confused, "Oh that's right, I didn't tell you yet, I'm sorry."

She then cleared her throat and looked at Rias with an almost emotionless face, "On the day Issei was born, I sensed that he possessed the Boosted Gear within him. Realizing dangers he'd be in if he were discovered I contacted my most trusted friends to place several seals on him so that his Holy and Dragon powers couldn't be detected. In my youth, I had many friends of the other races, including the Fallen Angel and Devil factions, all of who were willing to help me hide my son."

"We created seven seals and placed each one on top of another, to bind his power: 3 Angel Seals, 2 Devil Seals, 1 Mythos Seal and 1 Dragon Seal. While we were able to fully seal in his holy aura, every now and then a small bit of dragon aura would leak from the seals, so occasionally we would renew the seals. My husband and I wanted Issei to have a normal life, so we kept it secret from him and simply stayed in this area. I also placed an anti-detection seal on myself so as not to alert the devils in this area."

Rias sat there musing Sachiko's story, "That's quite a story," she said, "Getting not only members of the three factions, but even other races to help you hide Issei," Rias looked at her with a slight smirk, "You must be very well known." Sachiko just waved her hand in dismiss, "Oh no, I'm really just a no name angel," she said with a slight blush on her face, before reverting back to her serious face.

"When Issei introduced us to his girlfriend Yuuma, I knew she was a fallen angel, but assumed she didn't know anything about him and legitimately liked him. The fact he was wounded by light, says otherwise," she finished in a sad voice, and then she looked at Rias, "Rias-san, I have a request for you."

"Issei's murder by a fallen angel and your reincarnating him into a devil has broken two of the seals. It'll only be a matter of time before the rest of the seals fail and his power will be fully released. There are many from the other races and even some within the three factions who would see him as a threat and stop at nothing to destroy him."

"My friends would be happy to help out in any way they can, but many of them are in situations where they can only offer minimum assistance. Rias-san, please…please protect my son as much as you can."

"Of course, I'll protect him," Rias said assuredly, "After all, my servants are my family." Sachiko sighed in relief, "Thank you, Rias-san, thank you." Sachiko's halo and wings then disappeared as her eyes returned to brown and the faint wrinkles returned to her face. She then looked at the clock, "Good Lord! Is it that time already?! Come on, you and Issei will be late for school!" she brought Rias to the door, ran back for Issei and she and Mitsuru, saw them off as they left for school.

"Well, I've got to get to work now," Mitsuru said as he picked up his work bag and kissed his wife as she handed him a lunch box she packed since she had a little extra food from when she cooked dinner the night before, "Have a good day at work," she said, "I will," he replied, "and don't worry so much. Nothing bad is going to happen to Ise again, not if we have a say in it."

She smiled at her husband, "You're right, nothing will to Ise," she kissed him again and watched him as he went off to work, "Nothing will happen to him," she repeated silently as she thought to herself, "Not while we have a say in it!" she said firmly as she ran to the house phone and began dialing.

-At a Bathhouse in Heaven-

Nanael was sitting in a tub filled with bubble bath. She was had a young appearance, with ear-length light blue hair, green eyes and wings that were asymmetrical in size. "Ahh, this is the life!" she said as she relaxed in the bubble bath and "My work for the day is done, the bathhouses are open all day, and I don't have a care in the—"Lady Nanael! Lady Nanael!"

Nanael screamed startled by the sudden shout. She tried to stand but slipped on the bar of soap in the tub and fell in the tub with her bottom, sticking above the water. She was suddenly pulled out from under the water, "Lady Nanael, are you okay?" said the concerned voice of her protégée, Laila.

Laila was a young Nephilim with blonde hair, purple eyes one angel wing on her right and an artificial wing, called Nephilim's Plumage on her left. She wore a big red hat with a wing design in the front of it, a white breastplate on her torso, a red skirt with white ends, and white boots with wing-like attachments on each ankle.

"Laila!" Nanael yelled, "Don't just come in here screaming while I'm relaxing! You almost gave me a heart attack!"

"I'm sorry Lady Nanael! But I had to get this to you!" she held out a phone, "It's from Lady Sachiko!"

Nanael's entire mood changed in just a fraction of a second, "Tell her, I'm on my way!" she said as she quickly dried herself off and ran to the changing rooms and quickly dressed herself, in a white camisole with a short skirt, revealing her polka-dot panties, with steel-plate leggings, a steel gauntlet on her right arm and a long dueling glove on her left.

She quickly flew to her home, where Laila was waiting to hand the phone to her, "She's still on," Laila said as she handed her the phone. She thanked her protégée and but the phone to her face, "Sachiko! We haven't talked since forever! How's Ise doing? Is he eating right? Has he gotten taller? When can I come over and see him?"

"Calm down Nanael," Sachiko said, chuckling slightly, "I have something important to say; it involves Ise." Nanael only seemed to get more anxious, "Is he okay? He's not hurt is he? Oh no! Don't tell me he's gotten himself a…GIRLFRIEND?! NO NO NO! I WON'T ALLOW IT!"

"NANAEL!" Sachiko yelled into the phone, "Calm down, this is very important." She filled Nanael in on everything that happened in the past few days, and the situation at hand, "And that's where we are now, I was hoping you could help me protect Issei?"

"Of course I can," she replied, "Don't worry Sachiko! With the Angel of Light, Nanael's help, no one will lay a finger on my little Ise!"

-At the Hyoudou Residence -

"Thank you, Nanael, I knew could count on you." She then made to hang up the phone when Nanael called out, "WAIT WAIT WAIT! This 'Gremory' girl! What's she like?!" Sachiko knew that she meant, "Is she prettier than me?" and decided to be truthful, "Nanael, give up, she's gorgeous." And with that she hung up, and began dialing another number.

-At a Castle in the Underworld-

"Whadd'ya mean we're going to the Human world?!" yelled a young boy with, with blue-purple hair with antennae like bangs, red eyes, and pointed ears. He wore red shorts, red shoes, golden bracers and a long red cape. This is the Demon Prince Laharl.

"I got a call from an old friend of mine asking me for my help," replied a young girl with long blonde hair, red eyes, pointed ears, small red bat wings and a long red arrow-headed tail. She wore a red ribbon in her hair, which stood like bunny ears, a white lace dress with a red bow and red ribbons, red heels and a white bow on her tail. This is the Fallen Angel Flonne.

"I still don't see why we have to come along," said Laharl as he sat down in his throne, with his arms crossed like a spoiled child who didn't get his way. "Oh come on Prince, it could be fun!" said a girl with red hair tied into wild pigtails, red eyes, pointed ears, small red bat wings and a long red arrow-headed tail. She wore a black tube top, black miniskirt, a black choker, long black gloves and socks and grey boots. This is the 'Beauty Queen' Etna.

Flonne was packing all of their bags, with some help from the Prinnies, "You guys are coming, because this situation involves a member of the Gremory family and I don't have much experience with them," she said with a cheerful smile on her face. "The Gremorys?!" Laharl shouted quickly rising from his throne, "HA! You wouldn't think those guys were Devils, with the way they act. Those guys are an embarrassment to the Underworld!"

As Laharl ranted on about how he hated the Gremorys, Etna and Flonne talked about the situation. "Hmm, it SOUNDS interesting, but what do we get out of it, and don't just say 'something good'," Etna said. "I don't know," Flonne admitted as she continued to pack, "I just want to see Ise again," a light blush came to her face, as remembered the last time she saw Issei, oh how cute and innocent he was, she couldn't wait to see him again.

Etna for her part was thinking about Rias Gremory. Oh how she hated her elegant air, and her voluptuous figure. She looked down at her own underdeveloped body, and groaned in disappointment. And then she thought about her Queen, Akeno Himejima, and her jealousy reached critical mass, "That's it!" she said as she stood up with fire in her eyes, "I'm going to show those two that I can be far more attractive than the two of them put together!"

"Alright!" exclaimed Laharl, "I'll show those Devil wannabes what a TRUE Devil is like, then the Underworld will bow to ME!" And with that Laharl and Etna stood in the throne room laughing excessively, while Flonne continued to pack as she thought about Issei.

-At Devil May Cry-

"You're going to Japan?" said Lucia, a young woman, with long red hair in a braid over her left shoulder, brown eyes and dark skin. She wore a simple long sleeve tan shirt, tight blue jeans, brown shoes, and carried a pair of Cutlaseer at her hips. "Yeah, an old friend of Kyrie's from our Order of the Sword days asked me to help her son with a situation involving the Gremorys," said Nero, a young man with white hair, icy-blue eyes and a demonic arm with a glowing blue hand and a red armor-like skin covering most of his arm. He wore a black muscle-shirt, with dark pants, brown boots and carried a revolver at his side and had an engine sword, which he was doing maintenance on.

"The Gremorys?" Lucia asked, "Apparently, they're a family of high class devils," Nero explained, "and Sachiko's son was recently made in to a servant of the Gremory princess."

"So she wants you to free him from this girl's control," Lucia said assuredly, "Actually, that's not it," Nero said surprising Lucia, "Then what is it?" she asked. Nero quickly explained everything to her, about Issei being a nephilim, about the Boosted Gear in his arm, the seals placed on him to keep him hidden, his death by a fallen angel, and his rebirth as a devil.

When he was done, Lucia closed her eyes for a moment in silence as she thought about the day she learned that she was an artificial devil created by Arius. The truth weighed heavily on her until Dante helped her regain her spirit. Learning you're not what you thought you were could really destroy a person. This Issei boy, becoming a Devil is already going to be a shock for him, but discovering that he was never human to begin with...

"I'm going too," Lucia said firmly.

"What?" Nero said looking up at her in surprise.

"I'm going too," Lucia repeated, "I want to help."

"No way," Nero said, "Dante's still in the Underworld, Lady and Trish won't be back from their job for who knows HOW long, and there's no one around to take care of the shop!"

"Patty comes in and cleans up the shop all the time," Lucia replied, "There've been more and more devil hunters moving into to this area for the past year; some of them are indebted to Dante and can take over business until someone gets back."

Nero knew she had him beat, she countered out all of his arguments in just that one statement, "You sure you want to tag along?" Lucia smiled, "I wouldn't have said if I wasn't sure." Nero sighed, "Well start packing a lot of stuff, because we're going to be gone for a while."

And with that Lucia ran up the stairs to pack her bags, 'Well things are going to get even more complicated' thought Nero as he resumed maintenance on his sword.

Well, we're done here. If you have any questions, ask them and if the explanation doesn't have spoilers, I'll answer. If they do, you'll have to wait until I give you an explanation in the story. See ya next time!