Answers to reviews:

Son-Of-Scorn: There is a lot of plot. I am taking the time to develop relationships rather than have it straight up be 'women meets OC, womem spread their legs right away.'.

247 Raven: Anytime.

Disclaimer: I do not own High School DxD. I only own the OC Damian Mammon-Lucifer.


Three years have passed since the birth of Damian. He had proven to be quite a prodigy in those three years, learning to walk before crawling at six months old, saying his first word at ten months old. he was a bundle of joy, often running from his parents when they tired to take him for a bath but they eventually got him. But today, there was none of that. Today was arguably the most important event in Damian's life so far, not that he knew it yet. Clad in the finest Underworld clothing that could be made for a three-year-old, Damian and Sarlith came out of a transportation-circle, in front of a large castle.

A castle that was quite familiar to Sarlith in particular.

"Mum, why are we here?" Damian asked, looking quite curious about the castle as he tiled his head. He looked up at his mother, the head tilt and innocent expression looking quite adorable in his mother's eyes. "What is this place?"

"We're at the home of one of my best friends, Damian." Sarlith explained, patiently. "As well as someone that I'd rather like you to meet."

Mother and son made their way towards the steps leading up to the castle's doors, with said castle's doors opening on their own (likely pulled open from the inside) once they came close enough. Before they'd even stepped inside, Damian could see the castle's grand entrance hall, and noticed that it was rather similar to that of his own castle. Standing there were three people that he'd never seen before: a handsome crimson-haired man dressed in white, a gorgeous brunette woman- also dressed in white- and a little girl with crimson hair who could only be their daughter. She looked to be around the same age as Damian himself.

"Sarlith!" The brunette woman smiled happily as she stepped forward and shared a close hug with Sarlith, who also had a smile on her face. "So good to see you again, old friend."

Sarlith chuckled. "You as well, Venelana." She looked at the man as he walked over with the girl at his side. "Zeoticus, it's good to see you too."

Zeoticus let out a small chuckle as he shared a small hug with the Lady of the Mammon House. "Yes, you as well, Sarlith. I'm still surprised you accepted mine and Venelana's marriage when I remember you telling me to treat her right or you'd... ahem, well there are children here so I can't really repeat the words you said. But they were enough to scare me."

"Glad to see I still got the ability to scare people." Sarlith chuckled before she looked down at the small girl and smiled. "And hello again Rias. You may not remember me, since you were still a baby, but I'm a close friend of your mother's, I'm Sarlith Mammon-Lucifer."

Rias gave a small curtsy. "Nice to meet you, Lady Mammon-Lucifer!"

Sarlith gave a small giggle at Rias' words.

"Call me that in public, Rias. In private, you can just call me Auntie." she remarked, taking a small step aside so Damian (who had hidden behind one of his mother's legs while she was talking to Venelana and Zeoticus) came more into view.

"This is my son, Damian." Sarlith spoke. "He's about the same age as you, Rias."

Looking at her son, Sarlith gently nudged him forward, causing him to look up at her with a bit of a pout but his mother wasn't falling for it. "Go on, Damian. Introduce yourself."

Holding a sigh, Damian stepped forward and bowed a little to the girl. "Hi. My name is Damian Mammon-Lucifer. What's your name, Tomato hair?"

Rias gasped, her eyes widening while Zeoticus and Venelana blinked. Sarlith just sighed and pinched the bridge of her nose, muttering something about her husband being the blame for this.

"T-Tomato hair?! How dear you! My name is Rias Gremory! Heiress of the Gremory Household!" Rias announced proudly.

Damian stared at her for a few seconds before he smiled. "I like you. Your hair is really pretty. Reminds me ketchup sauce."

"You're trying to make fun of me, aren't you!" Rias pointed at him with a cute glare.

"Now, now, children, no fighting." Venelana chastised lightly with an amused expression on her face that was shared by her husband and Sarlith. "Rias, why don't you show Damian around? Show him your room? Your father and I will be in the living room with Sarlith should you need us."

"Okay Mom." Rias nodded before she grabbed Damian's hand and pulled him along. "Come on!"

"H-Hey! I can walk myself! Stop pulling!" Damian shouted.

The parents just laughed at the scene. "I think they'll be great friends." Zeoticus said.

"I hope so." Sarlith replied, watching Damian and Rias take off upstairs, before she followed her best friend and best friend's husband into the living room.


It didn't even feel like a second had passed for Damian before he and Rias were in the latter's bedroom, and Rias was showing him all manner of things that she'd received from all over the Underworld and Human World, all the while asking Damian just about every question possible about himself, about his life and just about everything else.

Meanwhile, all he'd managed to learn about Rias so far, aside from the fact that she was the Heiress of the Gremory Clan, was that her older brother was THE Sirzechs Lucifer, one of the Four Satans.

"Wait, your brother is THE Lucifer?" Damian asked with shock. He had read the stories of Sirzechs Lucifer, how he was a terror to his enemies during the Devil Civil War, and had a Peerage that was feared and made of strong servants that many call monsters purely because of how stroong they are. He also knew Sirzechs was married to Sylvia Lucifuge, and had her sister, Grayfia, as Queen of his Peerage.

"Uh-huh!" Rias nodded proudly before she pouted. "But he can be a really annoying big brother, sometimes. Every time he shows up he just embarrass me! Ugh, stupid older brother..."

Damian couldn't help but snort in amusement, which just made Rias giggle. The two were hit with a laughing bug as they started to laugh so hard that they clutched their sides, falling back onto Rias' bed, still laughing. Soon enough, they calmed down and sat on the edge of the bed.

"So, Damian, what do you do?" Rias asked curiously. "Back home. I mean."

"Do my lessons with my mother about our kind's society, be formal, read books. I happen to enjoy the classics humans make." Damian said with a smile.

"Oh? What kind?" Rias asked curiously, tilting her head which Damian had to admit was cute.

"Uhh... The Silence of the Lambs, which is about a serial killer named Buffalo Bill and the police group, the FBI, are trying to take him down, so they enlist the help of another serial killer named Hannibal Lecter, who is a cannibal." Damian explained.

"Eww!" Rias scrunched her face up in disgust. "Should you even be reading that?!"

"I used to... until Mum caught me." Damian said with a pout. "Was the only copy we had before she burned it. But aside from that book, I also read others. Some bout the supernatural, well the ways humans think of our world. But what about you, Rias?"

"Oh! I'm a big fan of anime and Japanese stuff!" Rias said with a smile. "Want to see?"

"...Sure." Something told Damian he's made a mistake.

His instinct was overall proven right, as Rias- with renewed gusto- dragged him through her entire collection of Japanese memerobelia and anime/manga collection, with her favourite anime seeming to be one about crime-fighting cats... that also made pizzas.

Yeah, he didn't get it either, but Rias absolutely ADORED it, having been gushing about it non-stop ever since Damian had pointed it out. Which she still continued to do by the time Sarlith and Venelana had come up to check on them.


EARLIER...

"So, how are things in your Clan's neck of the woods, Zeoticus?" Sarlith asked, sipping a cup of tea that one of the Gremory Clan's servants had provided a minute or so earlier.

They're going great." Zeoticus said with a smile, putting his own cup of tea on the table. "We have decided, for the future of the Household, to put Rias into an arranged marriage."

Sarlith paused at that and raised an eyebrow, looking at Venelana who seemed a little hesitant but she did seem to agree with her husband about this. The lady of the Mammon House put her cup of tea down, her expression turning serious as she stared at Zeoticus.

"Well, that's something to hear. I know our race always goes for those kind of things. The same happened for me and Revan, but we fell in love before a marriage arrangement could be proposed by the Elders." Sarlith said. "So, who do you have in mind to marry your daughter?"

"Riser Phenex."

There was silence for a moment as Sarlith took another sip of tea, mentally acknowledging what Zeoticus had just said. Riser was the third-in-line Heir of the Phenex Clan as of right now, meaning that he would probably never ascend to the title of Lord Phenex as long as either of his older brothers ended up having children. As well of that, his Clan's ability- Flaming Regeneration- was a powerful and respected one among the Clans that remained.

That power, as well as the Power of Destruction that Sarlith knew for a FACT that Rias had inherited from Venelana... the potential of a child that could wield both powers was immense. That was probably one of the main reasons why such a marriage had been arranged, and Sarlith couldn't deny that from that angle, the logic was pretty sound.

However, Sarlith had heard that Riser- who was a few years older than Rias right now- was to be blunt, a bit of a brat. There had been a couple of times where he'd acted out in front of other Underworld children, claiming his Clan to be the greatest and strongest of all Clans left in Hell. Childish bullshit, to be sure, but Sarlith was concerned that as Riser got older, such beliefs could manifest in more... damaging, ways.

Devils embodied the seven deadly sins, sometimes succumbing to one of the sins so much it was like a drug. Many had fallen for lust, lust for sex, for money, for fame, but the most well known and dangerous sin that lived in all Devils, especially the Pure-Bloods, would be the sin of pride.

Pride was as dangerous as the rest of the sins, and Devils were prideful creatures, selfish and greedy. It was clearly the pride of the Old Satan faction that had led them to wanting to continue the Great War, they couldn't accept a truce because their pride demanded that Devils win the war and be superior.

"Riser Phenex..." Sarlith inhaled then exhaled, pinching the bridge of her nose. "I'm not sure that would be quite a good choice, Zeoticus."

"What do you mean, Sarlith?" Venelana asked her old friend curiously.

"Look, to be blunt here, Riser Phenex is a little shit." Sarlith said bluntly. She was never one to hold back her honest opinion and always stated her opinion without a care for how blunt it was. If nobody liked it, then they could tell her, but she was a scary woman to piss off. "He's the third-in-line for his Clan, not the heir, and his attitude is something I frown upon. And I fear that as he grows older... he may be worse."

"Oh Sarlith, protective of your surrogate niece already?" Zeoticus chuckled fondly, dismissing her concerns for protectiveness over Rias. "Yes, Riser may have some attitude problems, but I'm sure he'll mellow out and Rias will think it's a good choice."

Alright." Sarlith replied. "I'll leave it in your hands. Not my place to really interfere in the business between two other Clans, anyway."

"Anyway," Venelana spoke up, after finishing her cup of tea. "Should we check on Rias and Damian, Sarlith? See if she's talked him to death already?"

"Sure." Sarlith nodded, letting out a small giggle. "Let's go together, Vene."


"Mum, can I come here again and play with Rias?" Damian asked once Sarlith and Venelana had gotten their respective children. Now, they were walking down towards the living room.

Sarlith smiled. "Oh, so you enjoyed spending time with her?"

"She's cool. Weird, but cool." Damian admitted.

"Hey! You're weird as well!" Rias exclaimed, puffing her cheeks at him. The two mothers just laughed at their children.

"Okay you two, time to say your goodbyes. I have to get Damian home for a bath before he continues his lessons." Sarlith said, getting a groan from Damian.

"Fiiiiine." he groaned, drawing out the word before looking over at Rias. "Bye, Rias. Hope I can see you again soon."

"Same!" Rias replied, dashing over to Damian and planting a kiss on his cheek, something that drew a raised eyebrow from Sarlith and a giggle from Venelana.

Damian said nothing for the duration of the walk from Rias' room down to the doors of the castle, after which he and his mother disappeared from Gremory territory through a transportation-circle.


I ain't the best at trying to show kids being kids, so I tried my best and SlashFan2018 helped out as best as he can with the chapter, so a big thanks for him helping me out with this story.

Harem: Rias Gremory, Akeno Himejima, Raynare, Kalawarner, Yubelluna, Xuelan, Karlamine, Tiamat, Yasaka, Kuroka, Gabriel, Grayfia Lucifuge, Serafall Leviathan, Venelana Gremory, Kiyome Abe, Seekvaira Agares.

Peerage:

King: Damian Mammon-Lucifer.

Queen: Unknown

Knight: Unknown

Knight: Unknown

Rook: Unknown

Rook: Unknown

Bishop: Unknown

Bishop: Unknown

Pawns: Unknown