Azazel watched as Junichiro descended into his thoughts with a smile on his face. He'd watched Junichiro pretty closely over the last year and had liked what he'd seen. He'd also learned a few things, at least until Junichiro had found and disabled all the spying magic he'd layered into the property. Any attempts to secretly replace them had been instantly foiled and Azazel had no idea how. That was pretty intriguing in itself. Eventually he got bored of watching Junichiro thinking and looked at what he'd been working on.
His eyes widened as he saw a new prosthetic arm sitting on the table in front of Junichiro. He'd been kept up to date on the replacements that had been made since the first wooden one they made together. Yet, this one, just on external looks, blew the last three completely out of the water. If he didn't know better, he'd swear there was a severed arm sitting on the table. Unable to resist his curiosity he opened his mouth to break Junichiro out of his thoughts, "Oho! Is that the newest model for your replacement arm?"
Brought out of his thoughts by the question, Junichiro looked down at his bench and couldn't help smiling brightly, "Indeed."
Laying on the bench was the fourth model for his replacement limb. The exterior was coated in doppelganger flesh. Not as creepy as it sounded as it wasn't actually the skin of a doppelganger, that was just what the alchemical creation was called. Using it let the thin membrane coating the arm take on the coloration of anything it was attached to, in this case it would be his stump. Even so it had a fleshy tone as its base color.
Beneath the layer of doppelganger flesh was a thin, relatively, layer of alchemically modified Adamantine. The modification was to make the usually very rigid, nigh unbendable metal, more flexible so it would appear to move and flex like muscles beneath flesh yet still be nigh unbreakable. Thin struts connected the exterior shell to an internal skeletal structure made of Blood Iron. Blood Iron, poorly named, had strength on par with Mithril, though weighed significantly more. It's special property was that channeling mana into it would cause it to make more of itself or, in other words, grow.
He chose that and designed the arm so that it could get bigger over time, he planned to have it for the next few years as it'd cost him the equivalent of hundreds of trillions of yen to create. The Blood Iron and Adamantine were just the two most expensive metals but not the only expensive things used in the construction. That didn't even cover the functions, hidden features, and things he had hidden in the space within the arm between the outer skin and bones. The whole thing was filled to the brim with high tier runes, still not top of the line but significantly more advanced than what he'd used on the first arm.
It took him three months to make the arm and it was his greatest creation so far.
Azazel fully stepped into the workshop and froze mid-step as a shiver ran down his spine, "What the hell?"
Junichiro looked over at Azazel in curiosity, "What?"
Azazel looked all over with a small frown of confusion on his face, "The magical density in here is ridiculous. I couldn't tell until I fully stepped inside."
Junichiro nodded in understanding, "Just a ward I set up with gather and restrain free floating magic in here. Takes a while to build up like this since it's not actively sucking it in from the environment, but any that naturally gathers in here never leaves unless its absorbed into something. Makes recharging my personal magical power and charging runes a lot easier."
Azazel nodded, "I can see how that would be useful." He rubbed his chin while resuming his walk toward the bench, "What would it take for you to install such a ward in my workshop?"
Junichiro seriously thought that offer over. Azazel was probably one of the richest people he knew and had a plethora of knowledge on all kinds of topics. Though one stuck out above others, "I'd be willing to do it in exchange for any information on Sacred Gears you'd be willing to share. I'm kind of interested in trying my hand at making my own."
Azazel smiled broadly, almost proudly, at that request, "I'm sure we can come to an arrangement. I wouldn't mind giving you copies of some of my earlier notes to help you get started. Though I would highly recommend putting in effort to study souls before you even try to make anything Sacred Gear related. One wrong step and you could accidentally destroy a soul."
Junichiro nodded in understanding. He had no intention of trying to run before he could walk. He knew exactly what could happen to someone that made a mistake with something dangerous or volatile. Death would be a mercy in some cases. Messing with something related so heavily to the soul? Yeah, he could easily imagine the amount of damage that could be caused by making a mistake. There were probably thousands of simpler ways to commit suicide!
That said, destroying a soul was not something that was easy to do and was the absolute worst case scenario of a runaway reaction, or something similar. He was probably more likely to accidentally release a soul from it's body or trap a soul somehow. Souls were durable and able to withstand a lot, especially those from more powerful beings. Still, destroying one was likely to be a sin of unimaginable depth and not something he wanted to risk on accident, especially not his own.
That over, Azazel finished closing the distance between them and looked over the arm laying on the table, "That's a pretty nice piece of equipment. It looks rather realistic."
Junichiro nodded, "I needed it to if I wanted to be able to go outside without having to use magic to keep people from looking at my prosthetic arm. Especially when it looks like medieval armor."