He took the bundles of Blood Iron fibers and began laying them down in layers that attached to specific points on the Blood Iron bones. He slowly and carefully used the medical text as directions on how to build up the layers of muscle that an arm would be expected to have. He added the Blood Iron strands layer by layer until the end product was an arm that looked like it had been flayed. The red color of the iron almost matching what one would expect flesh muscles to be colored.
Junichiro smiled as he picked up the arm in the gentle grip of his telekinesis and examined it one final time, "Looking good."
He moved the arm to the socket on his right arm and connected it to himself with a light click, "Time to test it."
With the arm attached, he didn't really try to think about what he wanted to do. The arm was designed to work on unconscious control just like his other one did. So, he simply tried lifting it. The arm instantly responded, the strands of Blood Iron contracting or expanding as flesh muscles would, only significantly faster. The arm snapped up faster than Junichiro could follow, the Blood Iron muscles making the arm significantly more powerful than he'd expected.
"Damn that's a snappy response."
He tried moving the arm again but focused on moving it slower, moving his left arm in tandem with the right to match their speeds. As he worked on getting a feel for the newly improved limb, he remembered why he needed to do so.
While he'd gotten some practice with his arm and fighting with it in spars at the various dojo's he visited, he'd never fought at such high speeds as he did in the fight yesterday. He'd known he would need to improve the arms strength, hence the Blood Iron muscle fibers, but not so soon. He'd wanted to make a few more upgrades then just install all of them at once. Now he'd do them as he finished them.
Why? Because yesterday he'd been forced to use Rapidly from Avalon to make his right arm match the speed of the rest of his body while using the enhanced speed granted to him by his sword. The principles that caused his arms to move were vastly different between right and left. This left the right lagging behind as it relied on magic to move while the left had magic and muscle. The difference wasn't too large, but he knew it would only get larger as his flesh and bones became stronger.
Hence the Blood Iron muscles complete with a rune array and enchantments to help the strands shrink and expand as needed while being nice and flexible without losing any of their durability. He would now literally have muscles as hard as iron.
After flexing the arm a bit more and getting used to the feel of it, he detached it once more and returned it to the bench. He needed to cover it back up and put the Doppelganger Flesh back over it to disguise it as a normal arm once more. Sadly, installing the muscles meant he had to remove a couple of the hidden surprises, to make room. He was happy he didn't have to remove them all though.
Junichiro smiled and lifted his arm in a casual wave, "Hey Kiba."
He'd just arrived at Kuoh Academy and found Kiba waiting for him at the entrance. Kiba turned toward him and gave a small polite bow, "Greetings Arai-san."
Junichiro waved the polite greeting off, "Just call me Junichiro. I'm not one for being overly polite."
Kiba just gave a polite smile and turned to gesture in the direction of the old school building, "Rias-sama is awaiting your arrival."
Junichiro rolled his eyes at the continued polite attitude, "You know that if I do join her peerage I'll expect you to treat me like a friend, right?"
Kiba just continued to smile politely. It was only then that Junichiro noticed a little twitch at the corner of Kiba's lips. The straitlaced guy was messing with him! That actually made Junichiro a bit happy. It'd been a long time since he'd had someone his own age to mess about with. There was just something nice about messing around and doing stupid stuff with guy friends that women would likely never understand. Something to look forward too!
The pair walked to the building where Kiba led him up to the second floor and a finely decorated room. Junichiro looked around and could tell they hadn't been using it for too long. It just didn't have that comfortable lived in feeling. Everything looked too... newly installed.
Everyone else was inside of the room, apparently awaiting his arrival. Rias gave him a bright smile, "Arai-san, right on time!"
Junichiro found and empty seat and carelessly flopped into it, "Alright, I'm only going to say this once, all of you are free to call me Junichiro, or even just Juni. No need to be overly polite. After all, if things go well, I'll be one of you soon enough."
He saw subtle looks from Kiba, Akeno, and Koneko directed at Rias along with the tiny nod Rias gave them in return. The interaction finished, Rias continued to give him a cheerful smile, "Then feel free to call me Rias."
Junichiro gave her a lazy salute and smile, "Sure thing, Rias."
Rias coughed to cover up the slight flush she got from him referring to her so intimately so soon, she'd expected him to be at least a little more restrained despite her words. She might not have been raised Japanese but she was an otaku of the highest order and it bled heavily into her daily life and personality. She cleared her throat before speaking once more, "I did have a question or two for you, feel free not to answer but I would appreciate it if you did."
"Ask away."
"Can you tell me why you don't want to attend school? I ask because we're planning to open Kuoh Academy to male students starting next year and I would like you to attend second year with myself and Akeno. You mentioned it in our negotiation and I wanted to get more details."
"It's simple really, school holds nothing I need. I'm sure you've realized the check I gave you was legitimate by now." Rias nodded so he continued, "I am independently wealthy. I could spend a ton of money daily and never run out. I don't need a normal education or a normal job, instead I focus on other things."
"What other things?"
Junichiro turned his focus to Akeno after she spoke, "I'll only talk about that if the contract between myself and Rias has been signed and I've joined the peerage. Until then, it's a secret!"