The next week, Kaiser asked for permission from his magical guardian, headmaster Albus Dumbledore, with the help of his head of the house, after Professor Flitwick called in a favor from someone who specialized in magical contracts to review it for him. After all, it's magically binding. If he doesn't adhere to the contract, it can either cost him his magic or his life. Albus readily agreed after reviewing the contract, which surprised Kaiser. He even praised him for his ingenuity. Perhaps he decided to change his strategy? Then again, he had the whole summer in where he could keep a close watch on him. Maybe even use a potion or two on his food, since Kaiser couldn't use magic during that time. Needless to say, Kaiser already had a solution for that particular problem. And he still had two months before the end of the school year.
Karl worked very fast. The next day after the contract had been signed, Kaiser received an expanded trunk, with its own pocket space. This is different from the traditional expansion charm. The expansion charm could manipulate space to a certain degree, so that the inside of an object looks bigger than the outside. But it has a limitation, and couldn't be used to fit a whole enchanting lab inside a trunk/suitcase. This trunk was enchanted in a more special way: It create an independent, pocket space. The limitation of the normal expansion charm does not apply to it. For example, you could place other expanded items, or other pocket dimensions inside.
The lab was really interesting. It contained state of the art enchanting and analysis equipment, along with a stasis chamber, storage room, bedroom, and a kitchen. It was more a gesture of good will than anything, and Kaiser appreciated it. While Rowena's equipment was really good, it was a thousand year old, and pretty outdated.
The storage room contained a different pieces of different materials, all at the sizes and shapes Kaiser mentioned. It would make sure that the manufacturing process would take less time than if he had to do everything himself. Magic allowed you to shape the material's to your heart's desire, while such shapes and internal details would require a huge amount of resources and technology to achieve without magic.
Kaiser transferred everything he gathered from the Room of Lost Things to the storage room, even one particular broken vanishing cabinet. He read about them, and he was exceedingly interested in them. They work a work of art, and they held a very special property: self-restoration. The creator had integrated a unique rune sequence, that would allow someone to fix a vanishing cabinet if he a specific spell, as long as the core component was intact. He was a genius. 'Such a shame the method to make them was lost to time…'
It was the weekend, so he began making watches. Everyday, someone was scheduled to come to school to collect the goods. Knowing Karl, Kaiser guessed the store where they'd operate was already getting ready.
Kaiser woke up early next Monday, as usual. He began his morning spell rotation, all silent, of course. They focused mainly on the Cutting, Piercing, Stunning and shielding spells. Though he added one verbal spell to them: The Killing Curse. He left it at last, but performed it nevertheless. He needed to get used to it, so he could eventually perform it silently. Say whatever you want about the Killing Curse, but it was useful. There was no denying that. It's a good thing the walls were enchanted with a Silencing Charm, otherwise all of Kaiser's year mates would be alarmed. He could, unfortunately, only cast it twice. It required an enormous amount of energy and concentration. Kaiser took a shower and spent the rest of the time reading in the RoR.
When it was time for breakfast, he headed to the Great Hall, but as soon as he entered, he noticed something was different. People were looking at him, the whole time. 'Very subtle…' He snorted internally.
He made his way to the Hufflepuff table, which wasn't odd considering this wasn't the first time he did so, and people got used to it. Not that he was the only one who did it, the older years did so all the time. Only the younger students seemed to take House Rivalry seriously.
"Good morning." Kaiser said, as he sat next to Cedric.
"Good morning to you. And congratulations on making the front page." Cedric said with a smile.
"Front page?" Kaiser asked, before he noticed the Daily Prophet newspaper in front of him. 'So that's why…'
The article spoke of a new store that opened in Diagon Alley in a good light, selling a runic watch made by a genius thirteen year old orphaned student, whom people had nothing but praise for. 'Karl really worked fast, huh…' He mused.
"Did you sell your runic sequence?" Cedric asked curiously.
"No, that would have been stupid." Kaiser shook his head, and Cedric agreed.
"Well, that means you're in danger. People are going to want that runic sequence, now that you're the sole owner. All they would see you as is a defenseless muggle-born student. You won't be protected at the orphanage you reside in." Cedric warned, and Kaiser smiled at his attempt to keep him alive. 'You're definitely surviving the Triwizard Tournament.' He thought.
"Actually, I'll be staying here at Hogwarts for the summer. Probably the other summers as well." Kaiser said loud enough for the neighboring students to hear. They'd probably spread the word.
"Good." Cedric nodded. "You couldn't find anywhere safer than Hogwarts."
"As long as the stairs don't kill me." Because that was apparently a thing.
The watch store had got a lot of orders as soon as it was announced in the Daily Prophet. Thankfully, Kaiser could keep up at the rate he's been producing the watches. Most students bought one, or had been gifted one by their families, seeing the use of such device. Some tried to buy one directly from Kaiser, hoping for a discounted price, but he explained to them in no uncertain terms that he couldn't do that, or he could risk breaking the magically binding contract he signed. And that led to a lot of questions about what a magically binding contract, with the older years doing most of the explaining.
By the end of the month, Kaiser could see that people already started developing dependency on the device, even those who didn't have it yet. You could see them asking their friends about the time every now and then. Which was a good sign for him.
One thing to mention is that Kaiser seemed to have triggered something he didn't expect. People were taking their studies a lot more seriously after seeing what he had achieved, and some second years started showing interest in Runes, conversing with him on the subject from time to time, including one Susan Bones. While she was a very cheerful person in the presence of her best friend, Hannah Abbot, who apparently gave her confidence, and made her feel in her comfort zone. Once you take Hannah out, she was suddenly this shy girl, who could barely put a sentence together. She had conversation about Runes several times in the library with Kaiser and Hermione, who refused to stop asking him questions, and was quite talented. You'd think the Hufflepuffs were underachievers, but that couldn't be further from the truth. She could stand her ground against Hermione was she applied herself. Kaiser, thanks to his Occlumency training, could stop himself from pulling his hair, and calmly answer Hermione's unending questions. Though, he enjoyed pointing at some book whenever she asked about something that could be found there.
One surprise, though, was that Harry Potter could be seen in the library some rare times, sitting with their group, which was definitely odd, considering his best friend was Ronald Weasley, the laziest person alive, though he accompanied him reluctantly when he had homework, and Hermione refused to spoon-feed it to him. Harry seemed awfully… ignorant, but Kaiser wasn't surprised.
Kaiser received a weekly reports about the progress that's been made so far. He also received a few request for higher quality watches. A few of them by Karl Greengrass himself. He either wanted them for himself, or wanted to offer them as gifts, and knowing him, if he offered them as gifts, he probably had something to gain from it. Either way, Kaiser would get payed, so he didn't care.
Kaiser had two other ongoing projects he was focused on. The first one is concerning the brooms. The second one, he won't be able to begin the runic scheme for this year, because he was still lacking in a certain subject: Transfiguration. Kaiser could see that Transfiguration had enormous potential, as long as you knew what you are doing. Because when you don't, the result is usually catastrophic. Students are forbidden from using transfiguration outside of class for a reason, so much that if you did, you could be directly expelled from the school, for endangering not only yourself, but your fellow students as well. Kaiser wasn't arrogant to think he was some master. He never practiced it outside of class, and listened to most what professor McGonagall lectured about.
Next year, he'd be able to perform it outside of class, but only the spells they've been taught. He'd need to ask the professor for extra classes, on what he wanted to achieve. She couldn't help him now, as she was very busing with the approaching exams.
Speaking of exams, Kaiser had been able to make a lot of friends during this period. There were a lot of rumors about him in the school, it had been progressive from the first year. First, he was a weirdo with crimson hair and eyes. Then, he was the nice person who helped everyone who asked for help, when it concerned homework. Next, he was the weirdo who could make him eyes and hair glow with frightening aura. Now he was the thirteen year old Runes genius, who helped anyone who asked for help. All students who had taken the elective made sure to use this opportunity, and that allowed Kaiser to make a lot of friends. Surprisingly, even some Slytherins approached him. Now, Kaiser wasn't one to judge someone as evil as long as he was sorted to Slytherin, because he knew a lot more about Salazar Slytherin than the others did, thanks to Rowena's Library. But it was the common consensus that Slytherins did not mix with the impure. Those that approached him apologized for their house behavior to him, and told him they had to play along to avoid getting into trouble. He did ask why they were approaching him now, and he was impressed by their strategy. It was the end of their school year, and they claimed to their house that it was the Slytherin thing to do to use people to their full potential for one's benefit. The blood supremacist bigots seemed to buy that, so the problem was solved.
The exams passed and the students left the school. Kaiser was left alone in the castle, with only the caretaker and the House Elves. The headmaster and the deputy headmistress came occasionally to take care of few matters, but most of the time they were absent. Professor Flitwick came to check occasionally.
Kaiser enjoyed the peace, an environment that allowed him to perform better, with no distractions. Regrettably, he couldn't use magic anymore, so his training had come to a stop, but it was replaced by more physical training and meditation.
He had succeeded in understanding the broom's runic scheme, and he was impressed. It did remind him of the time he'd been making Arduino Drones for fun. The brooms had all the drones components, except more precise, thanks to magic, with additional components, including voice recognition for the "Up" command, except it was a big different. The runic sequence couldn't be changed, and was hard-coded to only trigger when the command "Up" was said. The gyroscope was interesting. It did nothing but focus on the gravitational force, and calculate Euler's angles from the resulting vector. Unlike the electronic gyroscope he was used to, it didn't need to calculate the device's rotation speed, or have the energy hungry mechanical gyroscope to maintain three axis. The 'pitch' and 'roll' angles were deduced from the force vector, while the 'yaw' component wasn't necessary. Regrettably, the proportional error-correction method, which was pretty outdated.
The broom 'force generator' could use two different techniques: either manipulate air pressure or convert magical energy to an acceleration. The second one was the widely used method nowadays, at least for Quiddich brooms, otherwise, you might affect your surrounding. Because of the close proximity the players had to each other, it wasn't an option. There was no buttons for a broom's rider to press, and only controlled it with his body language, by leaning for the desired command.
Kaiser needed to practice drawing the runes first, and make sure he had enough control over them, before he could change anything. So, he divided his time between making watches, training, reading from Rowena's library and practicing Runes.