Disclaimer: I do NOT own Beelzebub! All recognizable characters belong to Tamura Ryuuhei.

Dedication: To all Tatsugarde fans, who have been patiently waiting for an update from me…

The Formula for Happiness

It was a normal Sunday morning. Well, it really was normal – as normal as it could be – until the blonde wet nurse, aka the Oga bride Hilda, came into the living room and joined the rest of the family – that was to say: grandparents Oga, aunt Misaki and the father-son duo.

"I'm pregnant."

"I know."

A weird dialogue started out of the blue in the Oga household. The first talker was standing up straight out of respect for her parents-in-law in the middle of the room, her hands entwined in front of her lap and her sharp green eyes piercing those of her opponent. The latter was sitting on the couch as everyone else did and responded to her indifferent look with a nonchalant one.

The parents of the young couple were simply shocked. That single word was enough to describe their faces, which turned to the young ones and each other alternately while multiple different thoughts occurred their minds.

The remaining two people continued watching TV as if nothing happened. Without showing any kind of emotion, Misaki petted the innocent baby on her lap and commented dryly. "Could you repeat that?" She was rather surprised by the reaction of her brother.

Hilda sighed and started anew. "Tatsumi…", she got used to calling him that way in front of his parents at least. "… I'm pregnant."

"Tell me something new, woman!" was Oga's answer, not much different from his previous one.

Misaki could virtually see how her father would react at any moment so she decided to spare her ears and her nephew that scene. "Come on, Beelze. Let's grab something to drink." She took the baby and went to the kitchen.

"T-Tatsumi…" his mother was the first one who broke the silence. "C-Can I talk to you a little bit?"

"Nah…" Oga stood up lazily and followed his mother upstairs. He exchanged a final blank face-to-face interaction with Hilda and left.

As soon as they stepped out, an immense amount of apologies fell down upon her. "HILDA-SANNN! Please, take a seat! You must sit down and rest yourself!" Oga's father took her arm and led her to the couch. "I'm sorry for my ignorant, insolent, impudent son! You can be assured that I'll make him take on responsibility!"

His performance was a déjà vu for Hilda and reminded her of the first day when she came to the Oga family.

Oga settled cozily on the floor while his mother stiffly took a seat on his bed. It took her a moment to calm down and she didn't know how to start or what exactly to say.

"Tatsumi… I'm sure that this was not the reaction that Hilda-chan expected from you earlier…" She remembered how her own husband had reacted back then: Mr. Oga had been overexcited and enthusiastic after finding out about his wife's pregnancy.

"What else should I say, mom?" Oga leaned back and yawned slothfully. "It's not my fault anyway, right?! Hilda should deal with her problems on her own!"

"Tatsumi!" His mother was outraged to hear that. "I just can't believe what you say!" It sounded as if Oga didn't want a second child considering his young age and school life. However, putting all the blame on Hilda was too much from a woman's point of view.

"What?!" Oga shrugged. "Guess that's how she's been educated! Not everyone's a great parent as me…" he bragged.

Mrs. Oga didn't quite understand what his first comment was supposed to mean. Therefore, she tied in with the 'parent'-part. "See? You've accepted Beel-chan, too. So… what's wrong with you this time?"

"Yeah, you're right, mom. It's all that brats fault! If it wasn't for Baby Beel, I wouldn't let that woman barge in my life that much! She's the one always pushing me around!" he complained about Hilda.

"So… Hilda-chan forced you…to do-… 'it'?" It was awkward for his mother to talk to her son about that matter, so she tried to use her words very carefully.

"Yeah!" His approval made her shriek lowly. "She made me take care of Beel! She left me no other choice but doing her bidding!"

His words were the truth behind his relationship with Hilda but they confused his clueless mother even more. "I'm not talking about Beel, Tatsumi. What about the second child?"

"The what?!" Oga was the clueless one now.

His mother got the feeling that they were talking at cross purposes in the last couple of minutes. "Tatsumi, do you even know what we're talking here about?"

Oga didn't have to reflect on it very long. "… about Hilda being regnant!"

His mother sighed deeply. "You've got something wrong there, dear."

Oga blinked. "Yeah?" Well, Hilda was quite regnant and bossing him around most of the time. But Oga had to admit that all of her requests were for Beel's sake, right? Nevertheless, she shouldn't proclaim it and say it out loud, particularly not in front of his family, which would present him like a bloody wimp!

Back to the topic, he wondered what else she could have said if it wasn't 'regnant'. "Did she say… 'pendant'?" he murmured to himself. "Does she want a damn pendant? No, mom! No way in hell I'm buying her something that expensive-…"

"Tatsumi, neither is it that!" His mother kneeled down in front of him and looked at him seriously. "Hilda-chan is…" she gestured a thick belly with her hands.

Misaki prepared a cup of coffee for herself while Baby Beel was busy with a bottle of milk in her arms.

"You know, Beel… I don't understand you guys."

"Nyo?" Beelze looked at his aunt curiously.

"Yeaaah, I mean you guys, geez! Especially that stupid father of yours!" She poured milk in her coffee and muttered to herself. "Not even my idiotic brother should show cool after hearing that Hilda-chan is-…"

"SHE'S WHAAAAAAAAT?!" Oga's loud yelling could be heard from upstairs, followed by his loud and fast footsteps.

"Well, that's a more likely reaction from him!" Misaki giggled to the infant in her arms and rushed. "Let's see how your daddy will make a bigger fool of himself!"

They entered the living room shortly before Oga and his mother. Once again, the family was assembled there with different expressions and reactions this time.

Hilda was comfortably lying on the couch since her father-in-law insisted on that. The latter hovered over her as if he was her personal server, which was somehow embarrassing to her. He didn't move from her side when Misaki and Baby Beel entered the room.

The next second, Oga and his mother arrived hastily. The main man entered the room stiffly and gulped heavily. There were many things that were troubling his mind and causing him a headache at the moment. He wanted to get rid of them and spit out all his wooly thoughts, shout them all at once but the only thing that was trying to come out of his mouth was her name. "H… H-H-H… Hil-…"

Oga took a sip of his tea as he finished telling the events of a few hours ago. "The next thing I remember is being hit by Baby Beel's electricity. Since I haven't woken up in my bed afterwards, I concluded it wasn't a fucking nightmare." He slightly winced at his own word choice. "Everyone was still gathered in the room and the first thing that came to my mind was grabbing Beel and rushing to your place – my most trustworthy ally!" he showed his counterpart a tense smile.

Furuichi was speechless. The popsicle he was holding tightly in his shaky hand began to melt and slowly dropped on his pants. Its cold feeling brought him back to his senses and he thought about his best friend's narration.

He finally understood why Oga and Beel suddenly barged in his house as if a demon haunted them. Not that Oga was scared of demons – unless that demon would be none other than Hilda! The impact that she had on Oga was beyond comparison, which even Baby Beel's biological father, the great Overlord in person, did not have. In fact, never before had Furuichi seen Oga running at that inhuman speed, as the silver-haired had watched him out of his window an hour ago, already hearing Oga shouting his name from miles away.

Now there they were sitting in his room when Oga was telling him the craziest story that he had ever heard from him. Well, Oga always succeeded in going beyond his limits and astonishing Furuichi somehow or other. However, what he told him just now was… Furuichi was plainly dumbfounded.

Oga noticed Furuichi's silence and his expressionless, pale face. "You're thinking the same as me, right dude? I can't even believe how a baby's supposed to fit in there! I mean-…" he pointed a finger at the naïve Baby Beel, "… just imagine something… someone… like him is inside your-…"

"ARE YOU KIDDIN' MEEEEE?!" Furuichi jumped and blew up in the end. "You're telling me that Hilda-san is p-p-pregnant and that's the only thing bothering you?!"

Oga backed off a little nervously. "W-what else-…"

Furuichi cut him off agitatedly. "Just how… w-when… did it happen?!"

"When you ask…" Oga pondered hard. "Perhaps… during our fight against Fuji?"

"Ugh…" Furuichi was tongue-tied as his face turned green this time and he just wanted to throw up. "D-during… fight?!" He restrained himself in disbelief. "What the hell were the TWO OF YOU DOING while everyone else was petrified?!" His face turned to an angry red as he continued changing colors like a chameleon.

The blank-faced Oga scratched his cheek and stared into space. He might be a fool – or at least, Hilda called him that most of the time – but he thought he wasn't a total idiot! He knew exactly that it required a man and a woman to make… something like Beel. The problem was that said woman was far away from him for a while, in the demon world to be more precise, so there were no man and woman nearby to begin with. In the event, he hadn't seen Hilda until the last fight against Fuji. And they barely touched each other back then…

Moreover, could a woman get pregnant by a single touch?

No, there was more behind it; Oga was quite sure of that! He remembered briefly and roughly what exactly that 'more behind it' meant, and concluded that Hilda could never be pregnant by him! No freakin' way! On first thought, he was relieved when he listened to the conversation in his mind. On the other hand, his conclusion aroused a different kind of fear in him. He felt very uneasy that the heat roamed up to his head.

Oga shook his head and strained his brain once again.

Hilda said she was pregnant. Not regnant. Pregnant! She wouldn't lie, no matter how much she impeded his life – she wouldn't lie to him, she never had. So, she was really pregnant. And her being pregnant… it couldn't be his… fault. And it couldn't be someone – anyone else's! Come on, who the hell would be stupid enough, or rather who would have a death wish and approach her more than five meters?

But acting on that assumption, it could only be himself when he eliminated Alain Delon or perhaps Furuichi, who actually had a death wish and tried to approach her too close for his taste. Finally, considering the fact that they were living under the same roof, Oga was the only one who would be able to draw nearer to her. It had to be his… fault. His brat!

Thus, demons could get pregnant without major physical contact?

And Oga had to take care of two brats now? His sleeping time, which was already shortened to five hours, would be even shorter now? He would share his croquettes with two – or three people now if he counted Hilda, too? Not only his food – also sleeping along with two babies – share his bed, his room, his whole life? The more he thought about it, the more he felt dizzy and was close to collapsing.

Furuichi let out a quiet sob and became noticeable. "I can't believe that you maliciously took advantage of the whole situation… behind Kunieda's back… and did that to my Hilda-chan…"

Oga didn't get how Kunieda got involved again but he reacted to another tiny fragment of Furuichi's words agitatedly and hit his friend with a knee-jerk reaction. "What do you mean, 'your'…?!" He mumbled under his breath.

A knocking on the door interrupted their conversation. "Oga-nii!" It was Furuichi's younger sister. "Uncle Oga has come for you."

"My old man?" Oga wondered and headed along with Furuichi downstairs.

The newcomer was already sitting on a couch and had a conversation with Furuichi's mother. The latter sent Oga a bright, albeit nervous smile. "Congratulations, Tatsumi-kun! You're becoming father… again…"

Said father didn't know how to react to this statement. His left eye twitched nervously. "…"

Furuichi had just enough of it how unfair life was and ran upstairs again. Oga stiffly tried to get a hold of his arm but he failed. Furuichi's mom also stood up and headed towards the kitchen. "I'm sure you both need to talk alone." She nodded to them and left them in privacy.

His dad gestured Oga to take a seat on the other couch across his so that they were facing each other now. Why did the elder man come anyway? Did Hilda send him to fetch Oga up? No, she would rather send Alain Delon since it would be faster that way.

"Tatsumi…" his father began, unnaturally silent. "Do you remember the first time you've met Beel-kun?"

He did very well. The moment when he found him by the river until they showed up at the Oga household together with Hilda, he remembered them all. His father was referring to the latter though.

Interpreting his son's silence as an affirmation, Mr. Oga adjusted his glasses and went on. "You were shocked and didn't quite know what to do. Being a father, it means taking more responsibility and the weight on your shoulders becomes heavier."

His father was literally right with the last part since Baby Beel always sat on his shoulder. He wondered where the conversation would lead and listened to elder man calmly whereas one foot was unconsciously tipping on the ground. It was the first time that Oga felt uncomfortable in front of his dad. He wouldn't even become nervous when he had gotten into mischief.

"However, as time passes by and you see your child growing up little by little, it just fills you with a huge bliss. He makes you happy whenever you look at his small face. No matter what kind of trouble you're in, he makes you forget about all of your worries."

"Dah?"

It was only then that Oga felt Beelze's small figure on his lap. He was so much bothered by the thought of a second child; he only considered the bad sides, the problems and constrictions of it. And now, looking into the big bright eyes of Baby Beel, he felt the true meaning of his father's words. He relaxed immediately and tightened his grip on him.

Mr. Oga continued softly. "And every time you notice that your child mature and mature more, you're very grateful to its mother that she made you a father. You remember why you've chosen her to share your life with, to be always by your side forever."

That was when he looked up from the infant into his father's gentle eyes. Oga saw that those words weren't meant to encourage or to persuade him. What Mr. Oga sincerely told him were about his feelings when he momentarily looked at his own son.

Oga hastily nodded at him as a sign of gratitude while his lips curved unknowingly to a smile.

"NOW then, Tatsumi!" His father jumped up and gave him a nasty shock. "What are you still doing here?! Go to your wife's side and support her like a man!"

Mr. Oga turned to his usual overreacting self again. Honestly, Oga was surprised to see his odd calm side from a couple of minutes ago, but he was more surprised to see how fast his old man returned to his standard personality. He knew how serious his father could be so he rushed to the door and headed home without thinking twice about it.

"And make sure to apologize for your foolish behavior!" Mr. Oga yelled into the bargain in such a way that his son could clearly hear it.

Two pairs of eyes observed the blonde inside the house through the window from outside. Oga and Baby Beel were behaving like housebreakers and couldn't enter their own home. Even if Mr. Oga's words helped him make up his mind, Oga himself didn't know how to face her yet. While Hilda was watching TV in the living room as if nothing happened at all, Oga just wanted to hide outside for the whole day, or better for months, to avoid a certain someone. Perhaps, he could just sneak inside and lock up himself in his room. But he couldn't get in unnoticed with Hilda and her sharp senses being in there.

"So… how is it going?" a voice whispered from the side.

"Not good! She just wouldn't move from her spot and-…" Oga replied in a whisper and stopped mid-sentence, wondering whom he was even talking to.

When he turned around and looked directly into Alain Delon's moustache, he almost cried out and fell back. His fist landed on his head and they both cowered away from the window.

"You idiot!" Oga hissed lowly but still menacing enough. "What the hell are you doing here?!"

Alain Delon rubbed his poor head innocently. "I came to say 'congratulations', Lord Oga." he whined already regretting his decision because he seemed to come at a wrong time.

"What?! How do you even know?!" Oga pointed an accusing finger at him.

Alain Delon scratched his head. "Well,… everyone in the demon world knows about it. Is it supposed to be a secret?"

Oga's mouth fell open and he became speechless. Did Hilda proclaim the news in this short amount of time? Or did they already know it before him? If Oga was really the last one who found out about her pregnancy – not counting Furuichi – then Hilda would have to pay for it.

"Alain Delon!" he packed the big man by his collar. "Teleport us into my room right now!"

"But Lord Oga…" the other man looked nervously. "Miss Hilda would notice my demonic powers at once." He had a point there. "So it would be in vain since you're trying to hide from Miss-…"

"I'm not hiding from her, dumbass!" Oga smacked him again and lied.

"Then, I don't understand why you're hesitating." Alain Delon rubbed the sore place that Oga hit. "There won't be any difference and you all will be living together again. Everybody knows that Lord Oga and Miss Hilda are a reliable couple."

Oga ignored the last word but he agreed with Alain Delon. Even if they argued most of the time, Oga had to admit that the baby stuff would be more annoying if Hilda wasn't around. She wasn't a wet nurse for nothing and she had proved her affection and loyalty for Baby Beel many times, even to the point of risking her own life. He would never say it aloud but Hilda was an excellent mother figure.

The father-son duo stood up from their spot behind the bushes. He shot Hilda one last glance before he made his way towards the entrance door. He just wanted to open it to confront the blonde at long last when he thought better of it. The voices of the other two females were coming from inside.

"I just can't believe you, Misaki!" His mom shrieked at her daughter.

"I know it was a bit harsh, mom." Misaki commented dryly. "But my little brother had to learn it the hard way."

"The hard way?" her mother repeated hysterically. "You told us that Hilda is pregnant just to make Tatsumi obey her?"

Oga froze by hearing that.

"It worked with dad, too, right?" Misaki explained herself. "Even if I was young, I remember how he reacted when you told him about your second time being pregnant! Dad acted like your servant…"

"But dear…" Mrs. Oga was embarrassed as the memory came back. "This is your father we're talking about. How could you assume that Tatsumi would behave the same way?"

Admittedly, Misaki didn't calculate that her brother would run away.

With a loud bang, the door slammed open and revealed an angry Oga. The two women were scared for a moment and saw by his reaction that Oga indeed heard their conversation. He didn't even bother looking at them as he passed by in frustration and went directly into the living room.

Hilda lifted her gaze from the screen and greeted her master with a charming smile. As soon as she saw Oga, her expression changed to a blank one, confusion hidden in her eyes. "What?"

"Why?" Oga shot back as calmly as he could. Although he was eased that the pregnancy stuff wasn't true and although it was Misaki's silly idea, he felt himself betrayed by Hilda somehow. The latter raised a brow, implying him to be more precise. "Why have you told me that you're pregnant?!" This time, a hint of disappointment escaped his tone.

Though Hilda caught it, she didn't understand the reason behind it. "I only said what Misaki's told me. I don't even know what it means."

With that said, Oga's frustration was blown away and he asked in disbelief. "W-WHAT?!"

Hilda explained further. "She's told me that it's the 'formula of happiness' or the 'strongest weapon of a woman to tame a man' or stuff like that." She believed the last part because it made someone strong as Oga run away like a coward.

"So, it's that bitch's fault!" Oga growled but it was everything he could do since he couldn't handle his sister. Not. His. Sister.

"Anyway…" Hilda's innocent voice interrupted his chain of thought. "What is 'pregnant'?"

His heart skipped a beat. A moment of silence filled the room, which felt like hours, as Oga reflected how he should answer to that. If he told her about his thoughts at Furuichi's house earlier… He gulped heavily since that would be his direct journey to hell without return.

In the meantime, Mr. Oga returned home with tons of baby stuff, clothes, furniture and toys. "Look what I've bought for our second grandchild, honey!" he beamed with enthusiasm and the other two felt almost sorry for him.

"Pregnant means…" Oga came up with a good explanation meanwhile. "… that Baby Beel would get another brother or sister!" he explained bluntly.

"It's not a lie then." Hilda stated as the other three entered the room. "I'm really pregnant."

Mrs. Oga and Misaki grinned widely whereas the other male adult didn't quite understand their reactions. Oga, who couldn't believe his ears, asked weakly with a shaky voice. "W-what?"

"Young Master will get a sister." Hilda simply said.

All family members except Oga gathered around Hilda to congratulate her and give her their best wishes while Hilda herself couldn't quite follow and smiled nervously.

Oga Tatsumi, who endured more than enough commotion for one day, collapsed with overwrought nerves in the end.

A/N: It was too much for him… poor Oga! That was the story how Baby Nico (may) have entered the Oga family. At least, Mr. Oga's presents weren't for nothing…

I've started this story a while ago and wanted to finish and publish it since "A Father, A Lover" isn't in process yet. I hope that you enjoyed this one as much as I enjoyed writing it! It's my second humorous one-shot after "A 'Lovely' Birthday Party" and such stories are inevitable for Beelzebub in my opinion. ;)

I'm eager to hear your opinions about this one and will wait for your reviews!