Disclaimer: I do not own Harry Potter or That time I got reincarnated as a Slime, their characters belong to their respected creators and should be given credit.

AN: Sorry it took long, I need the inspiration to write this and many things got in the way. Anyways enjoy the story.

Ch 1 Summer Vacation Start

Rimuru was…confused. He sat in his office doing his everyday duties as the leader of the Jura Tempest Federation. Mainly, he wanted to know what is bothering his son.

Ever since his son, Harry Tempest, or in other names Harry Potter returned from his Second Year of Hogwarts he had a surprise waiting for him. During his time at the school, there was an incident with the Witch of the Mirror, Izis.

The whole incident was just her obsession with Rimuru, which involves creating a pink Slime version from Shuna's dreams named Shinsha and mirror doppelgangers. The whole thing is confusing for the Demon Lord.

To better simplify things, Shinsha was on the verge of destroying herself along with Izis and Rimuru. But with his Ultimate Skill Core Manas: Ciel, Rimuru was able to stabilize her and now lives with him in Tempest as his daughter.

Izis on the other hand escaped through one of her mirrors and haven't seen her since.

For the time being, Rimuru will be on high alert for her. But the main issue is….

"Shion, is it normal for siblings to be awkward with each other?" Rimuru asked the Wicked Oni standing next to him.

The purple-haired Wicked Oni looks down at her master. "Mmmm, I'm not entirely sure Rimuru-sama. I haven't had any siblings when I was young, but I suggest you ask Shuna-sama and Benimaru." Shion suggested to her Lord. "After all, they are siblings."

Rimuru blinks, forgetting about that tidbit about those two. "You're right, thanks Shion!" He transformed into his Slime form, hopping to the door.

"Anytime, Rimuru-sama." Shion gleefully replied. "Um, Rimuru-sama where are you going?" She asked.

Rimuru turns around to the Wicked Oni, hearing her calling his name. "Mmm? I'm going to see Benimaru and Shuna." He explains to his Secretary still standing near his desk.

Shion blinks, tilting her head. "But didn't Benimaru say that he's busy training the new cadets for the military school?" She reminded the Demon Lord. "Oh, and Shuna-sama was busy with the merchants from El Dorado?" She informed the Slime.

"Gah! I forgot!" Rimuru chuckles, rubbing his head with his nubs. He looks to the side, wondering what to do now. "I guess I should see my kids then,"

{Reminder: Harry Tempest has his lessons with Diablo on his Magic, while Shinsha is with Veldora reading some manga you lent him.} Ceil informed her master of his children's activities.

Rimuru sighs, feeling like an idiot for not remembering his children's schedule for today. 'Oh, right…' He blinks before deciding what to do now. "I guess I should check on them," He started to himself.

Shion stands up, smiling at her Demon Lord. "Ah, you're going to see the young master and the young mistress, Rimuru-sama?" The Wicked Oni asked her lord and master. "Then allow me to travel with you then,"

"Sure, Shion. I'm happy to have you." Rimuru allowed his Secretary to come with him to check on the children.

"Thank you, Rimuru-sama!" Shion smiles, happy she was granted permission. She quickly rushed over to the Slime, picking him up from the ground. "Let's see both the young master and the young mistress, Rimuru-sama!" She walks out of the office, happily humming with Rimuru in her hand.

The two head out of the Town Hall, entering the busy streets of Rimuru City. The City became livelier and more progressive with the Aragog and his Driders now relocated in Tempest they became vital parts of the community.

The Driders have offered to be their transports and assistance to Geld's construction work. To put it simply, they became cranes and materials deliverers from one site to the other. In the end when a building that was due to be finished in two weeks decreased by only nine days.

Sure they have the Tempest Star Wolves to help transport materials. But due to their limited weight limits, it takes longer; that's where the two-week hinder comes from. But with the Driders strong abdomen and built the time span of transporting has been reduced.

One of the Driders passing through saw the Ruler of Tempest, he smiles at him and bowed. "Greetings Rimuru-sama," He greeted the Demon Lord.

"Hey, keep doing your work, my man." Rimuru greeted one of Aragog's people.

"Good day, Rimuru-sama," A female High Orc smiles at her Lord, walking with a female Drider,

The female Drider smiles at the Slime. "Yes, good day my lord." She greeted the Demon Lord of Tempest.

Rimuru looks at the both of them, "Same to you, have a nice day!" He greeted back, returning back to the road.

They smile before returning to their daily lives.

"The people of Tempest are very welcoming to the Driders, Rimuru-sama," Shion commented, watching a few of the Drider children playing with the other children. "Plus they are hard workers like everyone else. It shows that they are grateful for giving them a home." She smiles seeing the work they're showing from the jobs they found.

Rimuru nodded to Shion's statement, "Yes they have, Aragog's Driders are fitting well in the City. Speaking of Aragog," The Demon Lord saw the Drider leader they were speaking with Geld and a few High Orcs and Driders.

The Wicked Oni looks forward, seeing what her Lord was speaking about. "Ah, they must be discussing what to do with the construction site they are in," Shion commented, lifting the blue Slime to her face. "Shall we see what they're up to, my lord?" She asked the Demon Lord.

"Why not, we're near our home and have plenty of time," Rimuru stated as the two headed over to the construction site.

Geld points to the infrastructure they were working on and looked at Aragog's men. "Aragog, we need a few of your Driders to climb up to the top and lift the supplies from the ground so we can finish the second floor by sunset."

The grey-haired older Drider nodded, "Sounds like a plan, Geld-dono." Aragog turns to the Driders that are behind him for this project. "Alright, you guys heard Geld-dono. We are to lift heavy supplies for Geld's team to finish the second floor."

Aragog place a hand on his beard before looking at the supplies. "What are you thinking, Aragog-dono?" Geld asked, looking up from his clipboard.

"One thing," Aragog treads over to the workers, informing them something. "If I can get everyone's attention once more," Everyone turns back to the old Drider waiting for what Aragog's going to say.

"Bring the supplies that are easy to carry with you then bring the heaviest afterward." The Drider leader informed the construction team.

"Hai!"

The Driders and High Orcs went over to the caravan and took the supplies, doing what Aragog said.

Geld steps forward, standing next to the Drider leader. "Great call, Aragog-dono. Do you happen to be a construction expert?" The Barrier Lord commented on Aragog's knowledge of construction.

Aragog turns to one of the members of the Twelve Patrons of Rimuru. He smiles at the kind gesture of words for him. "When you live in a forest with your family, it's essential to make a shelter from the elements," Aragog explains to the Orc King. He generated webs in his hands, strong and durable when he stretches them.

"Though our webs are strong, knowing how to use them is viable." Aragog looks up at his people, shooting webs at the heaviest building material on the ground. "In this case, I knew that the heavy material is the ones that are difficult to carry from the ground. So-"

"Using the ability you determined that your people are the most capable of doing the difficult task that others cannot." Geld smiles, seeing that Aragog is more capable than he seems. "In any case, I'm happy that you were brought here by the young master."

Aragog nodded, grateful for the young Demon Lord. "Indeed, now my people have room to grow and interact with the others of our kind." The Drider Leader smiles, happy to finally have a true home to call theirs. "I'm not sure how I can repay Rimuru-sama or Harry-sama for this."

"Well, you can repay us by continuing to work hard in the jobs you and your people chose." The two monsters look behind them and saw Rimuru and Shion coming over to them.

Both Aragog and Geld incline their heads at the presence of the leader of Tempest. "Greetings Rimuru-sama," They greeted the Demon Lord.

"What's up my dudes, I see things are going smoothly here." Rimuru looks at the High Orcs and Driders working together to complete the task.

Geld nodded, "Yes, all of our previous City projects were completed a day earlier than the original date." He informed his Lord of the progress they made since Aragog, and his people came to Tempest. "Without Aragog-dono, things will be at their regular pace."

The old Drider looks over Geld, chuckling at the many comments by him. "Now, now, Geld-doo. We're merely just doing our parts to help this nation prosper." Aragog stated,

Rimuru sighs at the devotion the Drider leader has for his country. 'Is it me or that Aragog and his people are way too devoted.' The Slime thought, seeing both men getting along fine.

{Answer: The individual known as Aragog and his Driders are grateful for granting them a home they can call their own without being hunted or harmed.} Ceil informed the Demon Lord of what the new monsters were feeling.

'Pretty obvious, I can tell by their constant praises towards me and Harry.' Rimuru sighs mentally at the devotion they have. 'Maybe they have adopted everyone's habit of praising me and my family…' he ponders at their devotions to them.

{Answer: Yes.}

Rimuru frowns, hearing Ciel's snarky attitude when he ponders on things.

"Rimuru-sama, is there something you need of us?" Geld asked his Lord,

The blue Slime was about to answer the Barrier Lord on his reason for being here until Shion steps in. "Rimuru-sama wants to check on Aragog-dono and his people before heading to his home." The War Lord informed the two before them.

The grey-haired Drider nodded, "Ah, as I said before we're fitting in fine here in Tempest." Aragog smiles at the Demon Lord. "Other than that, we are…how you all say it…mmm ah! Peachy,"

"Indeed, I apologize for cutting this short Rimuru-sama, but we do have a unit to finish," Geld informed the two.

"Gotcha," Rimuru formed a thumbs up at the two construction workers. "Keep up the good work then, you guys!"

The High Orcs and the Driders incline their heads toward the ruler of the Jura Tempest Federation. "Thank you, Rimuru-sama." They lift their heads, seeing both Slime and Wicked Oni leaving the area.

Rimuru stretches his little nubs as Shion walks down the small neighborhood. "Ah, it's nice to know that Aragog's people are doing well," The Demon Lord stated.

Shion agrees, "Indeed, but they're not the only ones Rimuru-sama." The violet-haired Wicked Oni smiles, "Myrtle, Rima, and Darius are fitting in just well too."

"That's right, Myrtle was that ghost that haunted the girl's bathroom in Hogwarts," Rimuru stated, remembering seeing her floating around miserably. "I hadn't thought of it that much before but now I feel guilty for not doing something about her." He commented on his time as James Potter.

"That's in the past, Rimuru-sama. Now you don't have to worry about those you ignore back then." Shion smiles, seeing Rimuru's home just a few blocks away. "The young master will take care of those who were treated wrongly in his old World." She stated, having faith in the Arch Mage.

Rimuru sighs, smiling that probably is the case. "I believe you are right, Shion. Harry has developed a sense of right and wrong since he first came here." The Slime stated, taking note of his Son's development both in Magical and personal beliefs.

Just as the two heads arrive at Rimuru's home, a large pillar of fire rosed up from within the yard. "What was that!?" Rimuru exclaims, seeing the pillar of fire dissipating as it rose.

{Notice: A Magicule surge has appeared. Note, that this surge might originate from your son, Harry Tempest.} Ceil informed the Demon Lord of her scan of the area and the pillar of fire. {In addition, this might be the cause of the training session with the individual known as Diablo.}

'Thanks, Ceil, that has just increased my worry tenfold.' Rimuru sighs, sensing that his son has increased his power since he evolved.

Soon enough the front gate opened to reveal an Elf with long blonde hair wearing a suit and a ribbon around his neck. "Mmm? Oh, Lord Rimuru, Lady Shion, I didn't expect you to be home so soon," The Elf stated seeing the two.

"Darius, what has happened here?" Rimuru asked the Elf.

The Elf, Darius is formerly known as Dobby the House Elf stood calmly at his mistress's father. Upon his arrival in Tempest, he encountered a pink Slime when he was walking around the City.

She offered him a name that cause him to evolve into a Forest Elf from a House Elf.

"Ah, I presume you saw the fire bursting from your yard." Darius assumes that's the question his Lord was asking.

"Uh, yeah, this is my house and I want to know what's going on regarding my home," Rimuru stated to the newest member of his household's servants.

Darius nodded, "Of course, my Lord." He inclines his head to the Demon Lord of Tempest. He cleared his throat, turning to the entrance to the home. "Lord Diablo had the young master practice his newfound power. The pillar of fire you two saw was something that the young master trying a new spell." He explains to the father of the young master and mistress.

Shion's face brighten, hearing that Harry was exploring new powers. "It's great to hear that the young master's training. How is it going, Darius?" He asked the assistant butler.

Darius looks to the side, giving a nervous chuckle. "Well…" He scratches his cheeks, unsure how to answer the two about Harry.

'Why do I have an inkling feeling that it's not going well as they hope?' Rimuru sighs, catching the feeling in the air.

{Notice: Based on the individual known as Darius's actions. It's clear that your son is having trouble controlling his power.} Ceil informed the Demon Lord based on the Elf's movements.

Rimuru mentally sighs, hearing his Ultimate Skill state the obvious. 'I can tell that already.' He looks at Darius, curious about what Diablo is putting his son through. "Darius, if you don't mind can you take us to where Diablo and Harry are?" He asked the assistant butler.

"Of course, Lord Rimuru." Darius leads both the Demon Lord and the Wicked Oni inside the home where things are…iffy.

Harry huffs, sweating and exhausted by all the Magic lessons that Diablo had him do. His yellow eyes looked up to see ashes where test dummies were. "Mmmm," He turns his head to Diablo judging his Magic prowess.

"What is it?" Harry turns to his Magic mentor.

Diablo taps his chin, accumulating the things he saw from his young master. "Mmm, powerful and yet a bit flashy." He clasps his hands together, instructing the young Arch Mage. "

Harry wipes away the sweat from his head, a bit confused with what Diablo was saying. "What do you mean, Diablo?" He asked the Demon butler.

"As I said, your power is powerful but it's flashy young master." Diablo restated, turning to the newest maid to the household of Tempest. "Rima, if you would please take out the spare sparing-"

A pale blue-haired maid with fins for ears jumps, her breast bouncing as she did do. "H-Hai, Diablo-dono!" Rima, a Subgroup of Naga with the rare petrification eyes oblige the Demon's request.

Harry looks at his newest Subordinate as she passes both the Pale Hobgoblins, Alice and Alexis. "Uh, Rima you don't need to rush." He calls out to the blue hair Naga.

Rima joyfully turns around, almost stumbling over a rock. "Harry-sama, it's quite alri-AH!" She trips over only to be caught by a certain Storm Dragon.

Padfoot, Hedwig, and Ranga look up and saw the blue-haired Naga in the arms of the Storm Dragon.

"Woah there, careful now Rima," Veldora smirks at the newest citizen of Tempest. "That was almost a big spill there." He smirks at the young maiden.

Rima blushed, covering her face. "V-Veldora-sama! I'm terribly sorry for letting you catch me!" She got up and bow her head many times as an apology. "I'm sorry, I'm sorry, I'm sorry!"

Harry gave a light chuckle at the maid being clumsy as always. "Rima…." He smiles, shaking his head.

Veldora laughs, placing his hand on Rima's shoulders. "HAHAHAHAHAHA! There's nothing to worry about, Rima!"

Diablo sighs, "My apologies, Harry-sama. It seems that I still need to work with Rima to better handle her clumsiness." The Magic Lord informed the Arch Mage, trying to help the maid to overcome her clumsiness.

"Don't worry, Diablo!"

Harry froze then groaned, hearing a familiar cheery voice. "I'm sure that you can help Rima-chan overcome her flaw!" A pink Slime hops out of the living room and into the yard, transforming into a pink-haired girl wearing similar clothes to his-their father.

Shinsha gave cheery smiles, her hands behind her back. "And I'm sure that Rima-chan knows that and trusts you to help her!" She stated, has full trust in her family's Head Butler.

Diablo inclines his head, feeling honored by the young lady's trust in him. "Your words honor me, young lady." The Demon inclines her master's daughter.

Harry watches Shinsha, still comprehending that he has a sister now. He jumps seeing his so-called sister looking at him. "Onii-san, are done with today's training?" She asked him.

"Um…not really…" Harry looks at pink Slime, smiling at him.

"I'm sorry, young lady. Your brother has his sword lesson with Hakurou soon." Diablo informed the daughter of Rimuru.

Shinsha pouts, feeling like she hasn't really had the time to get to know her brother more ever since he came back from his school. She still puts a smile, knowing that there's a lot her older brother needs to learn. "It's alright, Diablo! I get that Onii-san has his lessons to get to with Gramps!" She turns to Harry, "Good luck with your training, Onii-san!"

"Y-Yeah…"

Rimuru and Shion stood on the pathway, watching the two siblings. "Is it me or that Harry seems to be uncomfortable around Shinsha?" The Demon Lord asked, sensing the awkwardness in the air.

Shion nods her head, sensing that as well. "Yes, unlike Benimaru or Shuna-sama, the young master seems to be unsure what to do with the young lady." The Wicked Oni stated from what she observed between them.

Darius nodded, agreeing with his fellow subordinate. "How do we suppose to rectify this gap between the two?" He asked, knowing that their lord and master wants both of them to better bond as siblings.

'So that's it,' Rimuru thought, understanding the plight of his children mainly Harry.

"Mmmm…."

{Answer: The best way to help with this situation is to…}

Later that night, Rimuru sat with his family at the dinner table. Shinsha to his left, Harry to the right, and Veldora…well…off reading Manga in his man cave.

Diablo, Alix, Alice, Darius, and Rima stood firmly at the side, waiting for the family to finish their meal.

Rimuru looks between his children, his elder son eating quietly while Shinsha was eating happily. "So…anything happens today you two?" The Slime asked his children.

Harry blinks at his dad, shaking his head. "Not really, just training-"

"Yeah! Onii-san has gained a new skill during the training with Diablo!" Shinsha jumps in her seat with excitement. "What's it called, Onii-san?"

"O-Oh, it's Flame Pillar," Harry answered, not delving deeper into it.

Rimuru sighs, confirming what he suspected was true. 'So Harry is really uncomfortable with having a sister. Man, I thought he was thrilled to have a sibling.' He thought to himself.

{Ahem…}

'Oh right! The plan!' Rimuru jumps slightly, being reminded by his Ultimate Skill of her plan. The Demon Lord cleared his throat, gaining his children's attention. "You two, I have an announcement to make." He stated.

"What is it, dad?" Harry asked his father, placing his utensils down.

"Is it something important?" Shinsha asked, sitting back down.

Rimuru smiles, "As you already know, it's the summer now. during this time of year, many things are going to happen." The Slime stated, informed the two of the plans.

Harry blinks, remembering the many events that happened last summer. "That's right, there was a summer festival before I came here, and my coronation-"

"Don't forget about your birthday, Onii-san!" Shinsha interjected, excited to celebrate that day with him.

Rimuru cleared his throat, having the table once more. "Anyways, the Summer Festival will be held two weeks from now."

Harry looks at his father, surprised that it was that close. "That soon? I thought it'll be in the middle of June?" He asked. "I just ended school a week and a half ago,"

"Yes, I know. But Tempest's watermelons are ready to be harvested and many more to come!" Rimuru cheered before stopping. He regains his composure and looks at the two. "I have many things planned to make the Summer more fun than the last year,"

'Plus it'll help both of you bond more' Rimuru chuckles within his mind, scheming many things.

Shinsha cheered, falling back to the floor. "Yay! I can't wait for the festival Papa!"

Veldora burst into the room, overhearing the festival planning. "We're having a festival? Well, my dear brother let's not dilly dally, we have fun to plan for my wonderful Nephew and Necie!" He laughs jumping around causing the servants of the household to smile.

Harry stands up, trying to stop his Uncle's celebration before he breaks something. "Uncle Veldora, you might break something. Calm down!" He waved his hands.

Shinsha joins in with their Uncle's cheering and jumping at the fun they're going to have.

"Shinsha, not you too!" Harry cried out.

Diablo sighs, watching the small family having fun from the news. "Well, nothing dull in the Tempest Household." He commented.

The rest agreed, silently nodding.

AN: How do you like it? The result for the polls' last story is down below.

Hufflepuff -12

Ravenclaw- 3

Gryffindor- 3

Slytherin- 1

ShinshaxDraco -10

ShinshaxCedric – 1

ShinshaxRon – 4