Hello everyone!

This is a very exciting story- it's a COMMISSION FIC! This idea came from Hikari!

I've never done a commission fic before, so this will be a lot of fun.

Couple things to be aware of- AU, mainly due to the fact that Leonardo now has a brother.

Also, updates may be slow. Sorry..

EDIT- Why doesn't anyone understand what an AU is? I HAVE NOT PLAYED AC3- I will not go digging around for potential spoilers- I didn't know Ezio speaks French, that's why the 'AU' disclaimer. So, fine, it's not Latin. Please stop complaining. It's a commission fic, stuff happens.

Anyways. Enjoy!

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Leonardo had always been fascinated by the idea of a keystone. A single stone that held up an entire structure, something so crucial that everything would crumble without it, become nothing at all. It had always been that sort of theory that fascinated him, the ones with the barest whisper of poetry to them. The idea that a single stone was the centre of the doorway's limited world, that one thing could ever be important enough to be not only instrumental in an existence, but be the existence itself – the idea is almost too beautiful for engineering, pure enough for art. He was fascinated, until this became the melody to which his world fell apart. Perhaps it was perfectly fitting, that he could assign his own devastation an explanation through engineering.

There was no sunlight in the morning. The sky outside was a dreary grey, rain in the streets if not yet bleeding from the sky. Leonardo was sitting at the table in his workshop, reading a letter, when the door burst open. He didn't look up, the sound of staggering footsteps across the floor and harsh, uneven breathing as familiar as his own heartbeat.

"Buon giorno, Ezio. I trust your mission was successful?" Leonardo looked up with a smile that quickly faltered, "I was not aware that you had a mission."

"No. No mission." Ezio fell into a chair across from Leonardo, looked at him for a moment, then stood up again. "What're you reading?"

"A letter from my brother."

"Ah." Ezio stared impassively at the floor, then his brow furrowed. "You have a brother?" Leonardo kept his attention to the page, refused to let disappointment register on his face. It should have ceased to be surprising, the amount that Ezio didn't know about him. Certainly the sudden revelations were frequent enough to ease him into the idea.

"Sì, Ezio. He lives with our father, in France."

"Ah." Another pause. "How's the letter?"

"Wonderful." Leonardo studied Ezio, as the assassin paced before the window. "He says "'Coepi amico opus patris nostri quod est engineer. Spero juvare se incepto ponte'" Leonardo said, watching him.

"That's good news," Ezio said. Leonardo sighed.

"Ezio, you do not speak Latin."

"I don't understand why that matters, Leonardo." He cast a look over his shoulder, as sharp as his tone was clipped.

"I just read to you from his letter," Leonardo said patiently, "it was in Latin, because he overuses every opportunity to practice his Latin. Perhaps you were not listening to me?" Ezio gave him an apologetic look. "I'm merely worried about you, amico mio. Are you feeling all right?" Ezio came to a stop across from him, leaned on the tabletop. His stare was unwavering, even if the look on his face was something far too akin to misery for Leonardo's comfort.

"Rosa is with child." Ezio hung his head, shoulders slumping. Leonardo could only stare. If Ezio was jealous of the man Rosa had been with – surely Leonardo's world would shudder, stumble, sink to its knees.

"Who-"

"Leonardo," Ezio breathed, fragile as anything the world ever put together from crystal as thin as silken threads, broken by a whisper, "it's mine."

The entire world crumbled to pieces when Ezio slammed his fist down on the table, breaking every hope Leonardo ever had that Ezio might love him back.

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Hope everyone liked that- please review!

Love ya,

Sunshine