A/N: Yes! I'm the first in this category! Hehehe... Anyway, here goes something new. I'm totally stuck with Harrold Jameson Potter-Hellsing so I thought of making myself unstuck by writing something like this particular story. So far only Slytherin remain a fanfiction of mine that does not start from his toddler year. I just love mixing Harry with numerous parenthood. When done right, it is an awesome read. After all , it is easier to control the story line by starting from the very beginning. Slytherin is an interesting case in my book in that I start from his third year onward. Another one is Post-Hogwarts and set in the Bleach universe called Viridian Eye, an UlquiHime fanfic with a very unique twist for Harry's involvement. Something no one so far that I knew ever tried. So I am keeping that under wraps. As for If You Say So, we concentrate more on SessKag, my kickstarter for fanfiction writing.

That said, this is a multi-crossover with concentration on HP/MTNN universe.

BLANKET DISCLAIMER: I SAY THIS ONCE, I WON'T SAY IT AGAIN. I DON'T OWN ANYTHING THAT IS OBVIOUSLY NOT MINE AND EVEN IF IT IS MINE, I DO NOT OWN IT BECAUSE THIS IS FANFICTION. DON'T SEND ME ALERT SAYING I DID NOT ADD A DISCLAIMER FOR THIS FRANCHISE AND STUFF BECAUSE I SAID IT NOW, I DON'T OWN IT. I GET NOTHING OUT OF THIS BUT EXPERIENCE AND ENJOYMENT. SO FAR, I DO NOT OWN HARRY POTTER, MAJIN TANTEI NOUGAMI NEURO, BLACK BUTLER, BLACK LAGOON, JORMUNGARD, HELLSING OR ANY FUTURE CROSSOVER THAT MAY BE GLIMPSED IN THIS FANFICTION.

PS: For those die hard fans of Black Butler, I am following Neuro's canon logic here; the stronger the demon the harder for them to live on the human plane. So following his logic, Neuro is stronger than Sebastian since Sebastian have been on Earth for centuries. This is mainly because in the MTNN canon, Neuro coming to Earth is like Yako diving into the sea for mussels. Look it up for further explanation. Don't come running to me saying 'hey, Sebastian is stronger than Neuro!' and etc, etc. Neuro can use the 7 Demon Courts Tools and I think someone who can get their hands on obviously high ranked items must be a somebody in Hell. Now enough with this, let's get this on!

Katsuragi Yako, a renowned teenage detective could only stare in disbelief at her mentor/partner as the mostly unknown to others demon Nougami Neuro stood there at the receiving area of England's London International Airport with a sleeping toddler in his arm. She wondered what was going on when the demon who just returned from the Underworld appeared before her while they were flying above Mexico only to disappear after giving the poor young detective an almost heart attack due to the pilot suddenly announcing that their radar had received a foreign matter detected to be attached to the side of the airplane.

She had seriously thought they were going to find out about Neuro especially when two military's jets appeared to survey the airplane's body only to find nothing.

Now she stood in front of the demon that set her on this course of private investigator with a toddler of a year old sleeping soundly in his arm. She knew Neuro can be random, impulsive and most of all crazy. But to think that he will kidnap a baby was a whole other crazy in Yako's book.

Yako sighed, "Neuro, put the baby back where you found him,"

Neuro immediately have that innocent look on his face, "But darling, how could you say that? After me and your lovely son stood here waiting for our beloved wife and mama to come home from her trip over sea?"

Yako stared at him…and stared…and stared…and stared…before his words sink in, "WHAT?!"

A few minutes later found Yako pacing in her hotel, "Neuro, I am not raising a baby that you kidnapped out of the blue!"

Neuro bounced the still sleeping toddler on his lap while giving her his familiar 'I-don't-give-a-shit' grin, "What makes you think that I kidnap this poor thing?"

Yako gave him her tired glare, "Really? Where else would the baby come from?"

Neuro gave her his familiar 'I'm-so-innocent-I-can't-do-wrong' face that only make her want to punch him harder, "Why, surely you know how babies are made? If you don't, I can give you the sordid details. After all, I do recall how you humans copulate. You see, to make a baby-,"

Yako blushed and snapped, "STOP!" She heaved while Neuro smiled with victory at making her all riled up. Taking a deep breath, she asked, "Where did you find the baby?"

Neuro answered, "On a doorstep out in the fall weather with nothing but his blanket and in a picnic basket,"

Yako glared at him and after studying the demon she realised that Neuro was being serious for once since his reappearance, which wasn't very long. She gasped and approached the sleeping baby before sighing, "He's just left there? How could anyone do that?"

Neuro shrugged, "Ah…the mystery of humanity's struggle for survival...still as delectable as always,"

Yako frowned at his words before her investigator trained mind realised what he meant. Quickly but as gently as she could, Yako took the toddler away from Neuro, "He is not food!"

Neuro pouted, "But Yako, I meant to raise him so that the mystery surrounding him will only grow. I don't even know his name! I could sense the mystery all the way from that hot country you fly from. Can you imagine the depth and size of this mystery? It is almost as strong at Sick's mystery and it is not even ripe for the taking! Surely you can understand the benefit of having the boy with us? After all, your tiny louse brain has grown larger from our last meeting. Large enough that it doesn't take me long at all to find you,"

Yako blushed, understanding from her experience that Neuro had just complimented her and that wasn't something to take in lightly. She sighed and looked at the sleeping toddler, "What am I going to do with you? Even if I send you to the authority, high chances are no one will pick you up. I'm still too young to be a mother, but who else do you have?" After all, she certainly didn't plan on becoming a mother by nineteen. Suddenly she noticed something, "Neuro…why isn't he waking up? From how you have been handling him to me snatching him from you, he should have been awake by now…"

Neuro gave her his familiar poker face, "I used the Evil Sleep on him so he won't be much fuss. Besides, babies need a lot of sleep,"

Yako felt a vein throbbed and her brow twitched, "NEURO!"

Neuro then snapped his fingers, brushing her scolding like one would a fly, as if a grand idea just lit up in him, "Yako, let's get married!"

Yako stared at him, for the second time that day rendered speechless before exploding, "WHAT?!"

Neuro looked at her with 'innocent confusion', "But Yako, from what I know a child needs a healthy environment with proper parental figure to grow into a genius. Surely you don't want him being bullied because we as his parents are not married?"

Yako blushed, "Even if I do adopt him, why would I need to m-m-marry you?" She stammered the impossible idea. She's tied enough to him without the nuptial vow thrown in. Neuro gave her his wicked crescent smile, "Now, now, lice…don't be a single cell that has no use to revolution whatsoever…."

Yako sweated bucket and tried to hold her own however despite having grown more matured in the last three years with her countless run ins with numerous crime lords in her career despite her age, Neuro somehow managed to reassert his dominion over her and Yako knew as much as she knew for certain three years ago upon their initial meeting; she can never over rule Nougami Neuro when he wants something.

Two months later, Katsuragi Yako officially became Nougami Yako…