With another large burst of his own power, he summoned the new blade in a flash of golden light. It was looking more and more likely that the color of the light related to the material of the weapon. White for mundane, golden for magical. He actually didn't appreciate that. Once he was more widely known, after joining Rias' peerage, it could give away the strengths and weaknesses of his blades to the observant. That was definitely annoying.
He wasn't sure if there was anything he could do about it, other than making all of his weapons from magical metals. He was hesitant to do that for now though. They really did take a fair bit more power to conjure than standard steel and his mana pool was still rather average. He'd not been forcing its growth. Frankly, he was tempted to throw himself at Rias the moment she arrived just so he could stop holding his magical growth back. The last thing he needed was to become too powerful for her to reincarnate. He was already pretty certain that his Artificing knowledge would make himself difficult to reincarnate.
He shook his head to get rid of those thoughts and instead decided to focus back on playing with his new Sacred Gear. He still had so many different ideas to test! He was definitely not going to get any sleep tonight if the excited grin he had was anything to go by. This looked to be all kinds of fun!
Junichiro spent some more time experimenting with his Sacred Gear before calling a stop to it. Or at least, a stop to making various different swords to test what he could do. He was pleasantly surprised to learn that size didn't matter with one of the experiments. As long as the thing he made could be identified as a 'sword' it could be small enough to fit on a charm bracelet. That, in and of itself, gave him a plethora of ideas.
Now though, he was using his diagnostic wands to perform scans of himself. He wanted to see what, if any, changes he needed to be aware of with his own body and soul. It was also his first chance to scan someone with a Sacred Gear within their body. If he was going to extract Boosted Gear from Issei, preferably without killing the guy, he would need to know a lot more about how a Sacred Gear was attached to a soul. Once he knew how it was attached, he could figure out how to detach it.
It wasn't just Issei he wouldn't mind stealing a Sacred Gear from. There were plenty of good ones out there and if he could take them from their owners, he could make life a lot easier for everyone. Joining Rias' peerage just meant he would be much more likely to run into those people. Or was it because Issei was the Red Dragon Emperor? Well, either way, he could get his hands on ones like Annihilation Maker, Blade Blacksmith, Dimension Lost, True Longinus, and so on from just the dicks in the Hero Faction. God he wanted to stomp those idiots SO badly. Stealing all of their Sacred Gears would render them non-entities.
It could also be used to help, such as in the case of Gasper. Poor kid had an amazingly powerful Sacred Gear that could stop time. But he was too weak to control it properly for quite a while. If he could take it out and just set it to the side for a while, Gasper would no longer fear it freezing the world and leaving him alone and could focus on growing stronger. Once he was strong enough it could be given back and trained with. Not to mention it would also stop one of the dumber plots early on in the canon, the events during the peace talks.
So, yeah. Being able to harmlessly remove Sacred Gears from people would be an excellent option to have at his disposal. He was sure he could figure out things to do with them, even if he couldn't, or wouldn't, install all of them inside of himself. Though if he stole True Longinus from Cao Cao, he was definitely keeping that one for himself.
The information he received from the scans didn't tell him a huge amount of information, but it did give him some. His previous scans, made to help construct better prosthetic arms and measure the growth of his magical core, had shown his body was made up of three distinct pieces. Those were his physical body, spiritual body or soul, and what he was dubbing the 'Magical Nervous System.' Unlike what one might expect, he didn't just have a 'core' within his meta-physiology that contained his mana. Rather it was that, plus a system throughout his body that allowed magical power to move through it. How else would the energy move to different parts of his body?
Now though, there was a fourth, metaphysical, part added to his body, the Sacred Gear. According to his scans it was located right next to his soul, sharing the same 'space' within him. They weren't totally intertwined or anything like that, but they were definitely connected and he could see how removing it wrong would kill someone. Damage to the soul was inherently worse than damage to the physical body. Given everything he knew the soul contained, that made perfect sense to him.
He'd need to scan a few more people with Sacred Gears, but from his initial findings, he was pretty certain he could remove his own Sacred Gear without killing himself. Doing it damage free and with ease though? Definitely needed more study and examples.
He set his tools back in their places and hummed to himself as he considered the things he'd learned today. It was only the loud sound of his stomach roaring for attention that drew him out of his contemplation. He decided to call it a night and made his way out of the workshop. As he stepped outside he saw that night had fallen, and fallen quite some time ago by the looks of it.
Stepping into the house revealed all was quiet. Mittelt was likely asleep already given the time. He felt kind of bad about that since he was supposed to be the one making her dinner. Normally she would have just stormed into his workshop and demanded he stop whatever he was doing and cook for her. He kind of found it a bit cute when she acted all snobbish and imperious with him, but only because he knew she was joking. At the same time, she also gave him his space when he was busy with something extra important or deep diving into something new and lost track of time.
Just a few more reasons to like her enough to date her.