Okay, so, this is an AU 'What if' story Mesacat13 (on Tumblr) came up and I asked if I could write. She said yes and here we are...
If you want to know more, keep reading and/or go on Tumblr and ask her yourself. She does some really amazing art of this =)

None of the things here belong to me - the idea is Mesa's - and I'm the writer. We'll be your supply of angst, suffering, some brotherly love and lots of sadness for... however long this takes. Enjoy =)

Chapter 1

They stood still, back to back to back to back, waiting, and taking in their surroundings. The room was silent, not even the breathing of the many people there hearable. It's only natural – they were all ninjas. The darkness was broken only by the moon's ray through the windows, landing in a circle around the four figures in the middle of the room. Well, four turtles to be exact, but it's not like it matters. With their eyes closed, they each took a small, silent breath and gripped their weapons tighter.

The shadows around moved quietly and quickly, almost with fear. And rightfully so. The four figures in the light might not look it, but they were the very best of ninjas here. And although they weren't human, they were highly respected and acknowledged among their peers and others who serve the clan.

Someone moved. The one with the staff – his eyes opened. Already, he scanned the dark area was forming a plan. His dark brown eyes danced from one corner to the next, catching every movement.

Next, the one with the dual katana. He slowly opened his blue eyes, his head going from left to right. He was assessing the danger, waiting like a predator to find a weak spot in the enemy's formation.

Then the third – the one with the twin sai. He growled, scaring any nearby shadows to move away. He looked ready to shred through anyone. He cracked his neck, giving a very threatening vibe towards the opponents around.

And finally, the fourth moved, holding his nunchakus with his hands and under his arms with a smirk on his lips and a glint in his eyes. If the third one scared the shadows, this one terrified them. He seemed more excited to fight than any of the others.

"How much longer do we need to wait?" the fourth one, smallest of them, asked, clearly impatient.

"Until the Master gives the word," the katana user answered back with some authority, his voice low and cold as he focused, like a leader would.

"Fearless Leader's right on this one – we don't need a repeat of last time…" the growling one grumbled. He was easily the most muscular of the four, yet seemed rather small.

"He's right you know… Besides, I found all of them…" the bo staff user shrugged, tallest and most skinny of them, a grin on his face as he pointed into the corner of the room.

"I counted twelve – three for each of us."

"Twelve against four? C'mon, that ain't fair. Don't they know they need to do better?"

"Yeah bro, I agree. Three just ain't good enough."

"Guys, focus… He's watching."

The four turned stone serious, getting back into the previous mood. Silence ruled over the room again, as four pairs of eyes flickered towards a figure standing on a balcony above the room, arms crossed over his chest and his cold eyes staring back. The moonlight reflected off his silver armor, weapons and even his helmet, giving him an even more menacing look.

"Begin," the man's voice was gruff and empty, almost cold; as all hell seemed to break lose.

The first one to get into a fight was the smallest one. He charged in, swinging his weapons around and knocking out one of his trio before the ninja had time to react. The other two jumped away to get some distance, but that did little to stop the nunchaku wielding ninja. With a grin, the little one extended the chain between wooden sticks and swung it towards one of the two, managing to chain him up. With some effort, he hurled the chained target into a wall, effectively knocking him out. Turning to the last one, he twirled the chain in the air, taunting his opponent. Seconds later, the last opponent was slammed to the ground, chained up and knocked out.

"And then there was one…"

On the far left side, there was a roar of anger and a distinct crash as someone went flying straight through the wooden wall of the room. The sai user bore his teeth, narrowing his eyes on the two ninjas. They each took a step back in fear, but managed to stand their ground and look the wild ninja in the eyes. Big mistake. In a moment, the muscular ninja charged forward, his speed much greater than the duos, and knocked them to the ground. He knocked one out with the blunt of his sai, while pinning the third one's arms to the ground with his weapons.

"Strike three… your out."

The tallest of the four jumped in the air to avoid the katana aimed for his legs, and smacked his staff into the attackers head, knocking him to the side. Landing neatly on the ground, he delivered another smack to the stomach, just to make sure. The other two charged forward, their weapons stabbing and slashing at him, yet the bo user evaded all of that. He moved away until he felt his shell against the wall and frowned slightly. The next attack, coming from a dagger, was blocked by his staff, while he used his long legs to kick the other ninja into the chest, sending him flying. The last one swung the katana at his head, but the taller ninja raised his bo and blocked again. Giving a grin, he simply lifted the staff quickly and let it hit directly into the opponent's jewels, making him drop to the ground in pain.

"You really should get some protection for that."

The leader locked blades with two of the three attackers, gritting his teeth in concentration. There were sparks flying in the air as metal met metal. Letting out a small growl, the turtle pushed at the locked blades, managing to free his weapon. As the two staggered a bit from the sudden push, he jumped into the air and used on leg for each of the two, and kicked them away. Landing perfectly on the ground, the leader slowly stood up and turned his attention to the last one, his eyes narrow. Without a sound, the last enemy ran forward, katana at the ready, before being blocked by two swords. As his blades locked once more, the shorter ninja used one of his legs to swipe at the other man's, managing to get him off balance. In the moment of weakness, the dual katana user moved like the wind, knocking his opponent to the ground and crossing his weapons around his neck, pinning him down.

"Well fought, but not good enough."

Silence was in the air again, accompanied by pants and groans from the beaten ninjas. The four quickly moved away from their locations and went under to the balcony, sitting down in front of the metal man with bowed heads.

"Michelangelo," the Master's voice echoed in the room and the said turtle winced at the tone. It didn't sound happy…

"You are quick and agile, yet play with your opponents too much. Give no quarter, no matter what," the smallest of the four bowed his head, eyes closed.

"Raphael," the sai user swallowed as he looked up. "Your aggression and strength might help you in most situations, but you do not think too far ahead. Never, under any circumstance, leave yourself weaponless," the said turtle bit his cheek and looked at the side.

"Donatello," the tallest of them blinked at the Master, hints of fear present. "Your deduction and perspective abilities serve you well, yet you allow the enemy to push you too far before you act. Use your instincts more if the situation comes," the bo user nodded solemnly.

"Leonardo," the leader looked up sharply, at attention. "Your skill with the blade is almost unrivaled, yet you forget you are in open combat. Always pay attention to your surroundings and do not let the enemy surprise you," the katana wielder gave a bow of his head.

"…Despite the mistakes you made today, this exercise was your best so far," the four beamed at the praise given, even if it wasn't much. "As such, I deem you ready to venture out into the city now. Naturally, you will be accompanied by either Tiger Claw or Bradford, but night patrols will be your main responsibility. I expect you all to preform your duties with seriousness and concentration as you've shown in your training."

The four were shocked to say the least. Finally, they were getting out of the lair and into the world! They've heard so much about it and only seen a few glimpse here and there, but now… now they were actually going to see it!

"Thank you, Master Shredder. We won't let you down," Leonardo said, remembering the gratitude they owed for this freedom.

"I know you won't."

"Yeah! Did you guys hear that?! We're finally gettin' outta this place!" Raph cheered, punching the air in his excitement. The tails of his black mask danced in the air as he moved, while the scarf wiggled. Then again, all four of them had the same attire – black masks, red scarfs, dark wraps around their fingers and legs and dark gloves up to their elbows.

"Raph, calm down! You know we're not supposed to be this excited," Leo frowned, his arms crossed over his plastron.

"C'mon dude, you can't say you ain't excited! C'mon, c'mon, c'mon," Mikey grinned, poking the leader in the shoulder.

"I'm with them on this one Leo. Just imagine what we can see and learn! It's impossible to not be excited!" Donnie smiled, giving a helpless shrug.

"Well, you can, if you're Leo the Bored!" the sai user smirked at his brother's expression.

"Ohhh snap! You just gonna let him say that?" the smallest ninja asked, trying to hide a grin.

"…You're right," there was a moment of dumb silence as the trio looked at their older brother in shock. Did… did they hear that right?

"We should be excited," Leo added, giving a smile. "I'm just… worried, you know? There are so many things that could happen and it would be my first real mission as leader… I just don't want any of you hurt," his voice dropped a bit as his brothers shared a look.

"Nothin's gonna happen Leo. We can take care of ourselves just fine, you saw that today. So stop bein' a downer and let's get movin'! Tiger is probably waitin' already!" the second oldest gave a smile, setting a hand on the leader's shoulder.

"Raph's right. The probability of us finding any actual trouble in the short time span we'll be outside is relatively low, especially considering the time and locations," Donnie summed up, smiling as his brothers tried to fully understand what he said.

"See? It'll be fine!" Mikey ginned wide, showing his white teeth.

"And if you're still, not convinced, Tiger is gonna be with us."

"I get it okay. I get your points," Leo laughed and shook his head. "Thanks," he added, looking at his brothers. "You guys ready to do this?"

"Heck yeah!"

"You are late, cubs," the firm voice of the turtles' trainer made them wince slightly.

"Forgive us Sensei, we were simply getting ready," Leo explained in short and moved closer to the tall Tiger mutant. He had his paws cross over his chest as he stood by the door.

"I take it the Master was pleased with your exercise?" the green animals gave a bit of a sheepish look. Honestly, they had the best relationship with Tiger Claw out of any other members of the Foot Clan. He was strict as shell, but he did care somewhere deep down. Or maybe he just didn't want to lose his snacks? One could never be too certain…

"We're here ain't we?" Raphael spoke up, shrugging it off as nothing.

"Fair point, cub. But today, we shall see just how much more improvement your skills will require," the older mutant moved to the door and opened it up, revealing the world of the turtles.

It was night, the sources of light being street lamps and an occasional light from a building. The air was chilly at first, but it quickly became a nice cool and comfortable temperature. There were some sounds of cars and TVs or radios as well as an occasional bird or cat. The four brothers stood with wide eyes and mouths, staring into the new, unknowing land.

"Now then, shall we proceed with our patrol?" Tiger managed to get them back to reality as the ninjas shook their heads to focus.

Okay, first one down. I'm posting this on Archive of our Own (or AO3 whatever you prefer) as well, and on my Tumblr blog 'shadow-is-upon-us' so if you want, you can follow, comment and share there as well.

Hope you enjoyed and if you did, do review! I always love to hear what the readers think =D