Pepper still had a mountain of company matters to handle and no intention of becoming a superhero.
After her injection, Leon personally escorted her back to Stark Tower.
Back at the Malibu workshop, Leon turned to Tony.
"So—what's the production rate on the Superhuman Serum?"
"That," Tony said, pulling up a massive holographic wall of molecular equations, "is exactly what I was about to explain."
"Several high-molecular compounds in the formula require extremely specific synthesis conditions. There's a luck component involved."
"The fact that I successfully produced three doses on my first run? That was basically divine favor."
"Unlike the Super Soldier Serum, this is not something we can mass-produce."
Leon nodded.
"That's fine. Actually, that's better."
"We only need it for people we trust."
The last thing they needed was the serum going mainstream—turning into some martial arts manual everyone had to learn or risk being left behind.
"Is the formula fully memorized?" Leon asked.
Tony scoffed.
"I improved it myself. Of course it's in my head."
"Good."
Leon didn't hesitate.
"J.A.R.V.I.S., send the digital formula to Arcee. Then delete every remaining electronic copy."
Tony immediately understood.
"Right. Strategic asset. Brothers-only."
"Exactly," Leon said. "I'm not letting Nick Fury quietly copy-paste this into S.H.I.E.L.D.'s database."
Tony grimaced.
Even if Fury wouldn't stoop that low—
Hackers might.
And if a supervillain with cyber abilities showed up?
Better safe than sorry.
They locked it down.
Leon requested a few additional doses.
One was reserved for Dr. Helen Cho once the Regeneration Cradle was completed—framed as a reward.
Another was tentatively planned for Rhodey.
But after just receiving a War Machine armor worth billions, Rhodey might hesitate to accept more.
Timing mattered.
As for the others?
Leon and most of them were still in the "casual" category.
Heart before serum.
Arcee's Upgrade
Now—
The real project began.
When Leon pulled 1000 kg of unshaped Adamantium from System storage—
Even through the faint blue System barrier, Tony's eyes locked onto the liquid silver metal instantly.
"That's not normal."
When Leon explained that Adamantium was harder than Vibranium—
Tony immediately tried to claim it for the Mark VI armor.
Denied.
"Why?!" Tony looked personally betrayed.
"These are for Arcee," Leon explained. "Your armor materials are handled separately."
Tony switched expressions instantly.
"Ah. That's fine then."
The emotional whiplash was incredible.
Tony redesigned Arcee's propulsion systems around the new element.
Leon, assisted by J.A.R.V.I.S. and Dum-E's robotic siblings, forged precision molds according to Tony's schematics.
If Tony had better mastery of his magnetic powers, he could have shaped the Adamantium directly.
But he wasn't there yet.
Soon—
All hard-component molds were ready.
Tony stepped forward dramatically.
With a conductor's flourish, he raised his hands.
Liquid Adamantium separated from the System's protective field and levitated.
It portioned itself precisely into mold allocations.
Tony glanced smugly at Leon.
Impressed yet?
"Hurry up," Leon said dryly. "It's solidifying."
Sure enough, the liquid metal was thickening—transitioning toward its near-indestructible state.
Tony refocused.
Streams of liquid Adamantium poured into molds—
Cooling within moments into permanent, unbreakable structural components.
"These are just the rigid frame and armor," Tony said. "What about flexible components? Tires? Joints?"
"Vibranium," Leon replied.
Manufactured via the Regeneration Cradle—programmable, adaptable.
The production was already underway in Leon's lower workshop.
Arcee Appears
The elevator opened.
Arcee stepped out in Partner Mode.
"Thank you, Tony."
She bowed formally.
Tony blinked.
"Did she just—"
"You heard correctly," Arcee confirmed sweetly. "Leon's brother."
She winked at Leon as she passed.
Leon silently zipped his lips.
Tony deflated.
"…I must've imagined it."
Leon helped move the components into his private workshop.
But before long—
He was kicked out.
Because instead of assisting efficiently, he kept touching parts unnecessarily.
Productivity suffered.
Reluctantly, Leon returned upstairs to help Tony finish the Mark VI.
The designs were complete.
Only materials remained.
Leon stepped forward.
He shifted his body.
From right shoulder to fingertips—
Flesh receded.
Revealing gleaming, living Adamantium skeleton.
"Whoa, whoa, whoa!" Tony shouted. "I was joking before!"
"I'm not."
Leon calmly disconnected his right arm at the joint.
No struggle.
No hesitation.
The tendons retracted cleanly at his will.
He handed over the Adamantium skeletal structure.
"This is the strongest regenerative material on Earth."
"And it was always meant for your armor."
Tony stared at it.
Then at Leon.
No more theatrics.
No more protest.
"Yeah," he said quietly. "Brothers."
They both knew the rest.
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