I wanted to put a few more chapters in before I launched into my bigger arc, but I couldn't not start it. A lot of things inspired me and as any writer can tell you when you get inspired you have to write it - now. One source of inspiration was a picture posted by tmntgurl on tumblr. I don't think they drew it, but it was really great. Also my new favorite song "Say Something" drove me to write it too. It is also great. If you haven't heard the song you must go listen now. It's by A Great Big World.

So without further ado I present to you the beginning of an arc. Enjoy!

As the weeks go by Donnie continues to see Alopex. The lies he concocts to deceive his brothers have to become more elaborate and more convincing. Alopex helps him with the latter part. He gradually becomes a better liar. Still, that doesn't stop Raph's suspicion from growing. Donnie can feel his eyes on him with increasing frequency after that night with Leo's sneezing. But it just means Donnie has to try harder.

He is careful to make sure Raph isn't following him when he leaves and those times where Raph is Donnie makes sure not to go anywhere near Alopex. It irritates him not to go – he goes every day now – but ultimately it's the only way. He leads Raph to areas where they generally scavenge for parts. Still, he knows Raph knows what he's doing. It only keeps Raph from discovering the truth. No more and no less.

He hates to say it, but as well as lying he does other things because of her. He also goes on another mission or two with Alopex. She drags him along, but at the same time he willingly goes. He hates every minute of the injustice, but loves every minute by her side. He wishes he didn't, but no matter what he tells himself he follows nonetheless.

It is only on one night when the suspicion has reached an all-time high that everything goes spiraling out of control. They are out scouting again because of the robberies. Donnie isn't particularly worried. They've been doing this for months and become no more aware of her. Still, there is no denying the air is thick with tension. Raph watches Donnie carefully and Leo's mind is forever stuck on the real culprit for the distance that has been forced between him and Donnie. His 'allergies', as Raph called them, had not relented since that first day. And it unsettles him greatly. There is a secret here. He just doesn't know how to find it.

Even Mikey feels it. He understands Donnie and his behavior are the culprit, he just is completely lost as to why. He does not harbor suspicion in the least. He only worries for the relationships between the others. He wants to say something too, but he's tried to say something a million times by now and all it does is create more problems. So he keeps his head down and runs along with the others in silence.

They inspect the first spot together and find nothing. Only then does Leo speak and direct them to each go to another place. They all nod and turn to go their separate ways. Then Mikey shrieks, a terrible eat piercing sound. The others whirl around with their faces set to reprimand their little brother until they too lay eyes on the reason for it.

The angry looks slip from their faces and stark terror takes its place. Their blood runs cold and the color drains from their faces. It is Slash who towers over their small brother. Malice curls his lips and a bloodlust shines in his sea green eyes.

In the next instant Mikey is smacked across the roof. Slash delivers a harsh blow to his face, leaving a dark mark behind.

"Mikey!" All three scream, but none as loudly and desperately as Raph. He clenches his hands into trembling fists and glares viciously at Slash.

Slash grins cruelly over at Raph. He has eyes for no one else in that instant. "I'm back Raphael." He curls his hands into fists big enough to swallow Raph. "And this time I'm not going to spare you – any of you."

Raph growls furiously and forces the terror down. Memories flash before his eyes regardless, yet they do not hinder him. They only make his heart beat faster as he charges for Slash.

"Raph!" Leo reaches after his brother. But it's no use. "We can't…" He sighs in aggravation, cutting himself off. Their best bet is to run. Yet they can't run forever. And they've gotten better. So he flies after his brother.

Donnie trembles where he stands. He remembers all too well what Slash did last time – to him, to his brothers, and everything. His arm aches with just the memory. He grabs at it instinctively and looks down at the pressure there.

He's ridiculous. This is no time for nightmares and flashbacks. He jerks his head around, away from Slash. He races toward Mikey instead. His brothers need his help to fight, but he needs to check on Mikey. No, you need to prolong the wait to the inevitable pain. No! That's not it! It is…not! He's a ninja. He fears not pain.

Donnie shakes the thoughts away and drops to his knees by Mikey. "Mikey." He calls urgently. "Mikey, are you ok?" It was just one hit. He'll be fine. You know that. You're just being a coward. Am not! He reaches out and lifts Mikey up.

Mikey groans and slowly opens his eyes. "That…hurt." He says vaguely.

Donnie lets out a breath. "It's Slash." Sweat trickles down the back of his neck and his throat runs dry just saying his name. "He's back."

Mikey snaps to attention. "Oh man!" His eyes are wide and wild. He leaps up and his hands snap out to grab his weapons. There is a slight tremor about him and his focus is much sharper than usual. "We gotta help!" Together they can surely do this. It won't be like last time. They won't get separated.

Raph drives his sais down at Slash. His movement is harsh, but without focus. He misses terribly.

Slash sidesteps and makes a fierce uppercut.

Raph takes the blow full force. His teeth smash against each other and he tastes metal. He stumbles back, dizzy and disoriented. The blood fills his mouth and trickles out the edges.

Slash darts forward. He draws his weapon and slams it into Raph's chest. He hears the sickening sound of metal cutting through the plastron and digging all the way through to the skin. It sends a shudder through him – one he eagerly works to duplicate.

Raph screams. His body seizes in pain, but he fights through it. He jams his sais into Slash's arm. He breaks the skin and red seeps out around his weapon.

Slash roars and jerks back his weapon. He stumbles back, but he does not lose more than a moment. He swings his weapon back and launches it forward.

Raph groans and hunches over. His fury is peaked and his desire greater than ever, but the pain is more than he can bear. He clutches at his gaping chest wound and has no time to block or dodge. Bad ninja… his mind curses. So bad.

"No!" Leo snarls. He brings his katanas down hard on ball of Slash's weapon, forcing it to the ground and away from Raph. He glowers unforgivingly up at Slash.

Raph rights himself and prepares to charge back in. He can't let Leo fight alone. That's what happened last time, happened with Donnie and Mikey. And they were beaten terribly. Not again. No. Not again.

Slash flings his weapon up, knocking Leo's katanas back. He swings it furiously at Leo's head.

Leo leaps back. He makes sure to keep himself between Slash and Raph. "Raph," He says sharply. "Get back. Now."

"What?" Raph gasps. The severe reaction causes a sharp pain to spring from his chest and he doubles over. "No…No way." He grips his weapons as tight as he can. "I won't let you fight him alone."

"I'm not alone Raph." Leo waits a fraction of a second and then springs forward. He doesn't capitalize on killing, but he aims for blood this time. He swings his blades at Slash.

"Leo!" Raph curses. He chokes on his words and coughs up blood.

Mikey jumps from behind and throws his nunchucks.

Slash twists around and closes his hand around Mikey's weapon at the last second. He jerks it forward and flings Mikey along with it.

Leo comes to an abrupt halt as Mikey comes flying toward him. He swings his arms out so his blades are away from his brother and in the next instant they come crashing together. They sprawl out in a heap on the roof.

Slash laughs maniacally. "You're not better than before." He throws his weapon to the side and jumps to the heap of them. "Even together." He brings his fist down on them.

The two scrabble apart. They avoid the brunt of it, but Slash still manages to clip Leo on the shoulder. The blow back against the concrete is worse than the strike and Leo gasps as his head snaps back and then forward again. He hears the crack of his skull as much as he feels it.

"Leo!" Mikey wails. He doesn't hesitate even as his heart quivers. He triggers the blade of his weapon and launches it at Slash with a vengeance.

Slash growls deep in his throat. Nuisance. He snaps his hand out and willingly takes the blade, letting it sink deep into his palm as he catches it and holds it tight.

Mikey gasps and his eyes shoot open wide.

Slash pivots and turns Mikey's own weapon against him. He brings the blade down across the turtle's arm, splitting it down the middle.

Mikey screams, a blood chilling scream. But he does not lose his chance. He drives his other blade deep into Slash's arm.

Raph jerks up, pain racing through him but it meaning nothing. A terrible fear twists his gut as the dark red stands out against Mikey's skin. "M-Mikey!" He charges toward them, his sais raised.

Slash smashes his fist into Mikey's skull.

Mikey gasps and is thrown by the blow, but he does not release his weapon. He remains close and lifts and plunges the blade again.

Slash roars in Mikey's face and extends his claws, much sharper this time. He draws them over Mikey's face again and again. He scrapes at him everywhere he can.

Finally Mikey can't take it anymore. He relents, losing his hold on his weapon.

Slash uses this. He lays another punch on Mikey.

Mikey is throw back. He skids across the roof, tearing up skin and very nearly sliding off the roof. He stops just at the edge. He groans and his fingers twitch slightly as he tries to move. But he can't. His limbs won't cooperate. All he can do is breath shakily in and out.

Raph jumps at Slash. He thrusts his sais down at his head. He could have never done it before – their last fight – but he knows now it's the only way.

Slash spins quickly. He takes a hold of Raph's wrists and stops the blow inches before contact. "They say don't bite the hand that feeds you."

Raph starts. He kicks out and flails to get in a good hit to free himself.

Slash opens his jaws wide. "But you don't feed me anymore." He lunges forward and sinks his teeth into Raph's shoulder.

Raph's scream is blood curdling. It stops all their hearts and steals their breath away. "Raphie…" Mikey chokes out weakly. He reaches feebly toward his brother. As if he can really save him like this.

Leo pushes himself up. His head throbs and his world continues to spin even after all this time. Blood drenches the back of his head and he wobbles on his feet. Still, he pushes forward. "Let him go!"

Donnie stands terror struck in the background. His brothers fall one by one and yet he can't even move. His heart trembles fiercely. No…it can't be happening again. It just can't. And look at you, standing there like a helpless child. Pathetic. It is! He knows it. No…there must be a way.

He sucks in a soft breath then and jerks his head up. He forces himself to see the red splattering across the sidewalk in order to also see Slash. "Hey," He yells as loud as he can. "Slash!"

Slash releases Raph's shoulder and drops him carelessly. "Huh?" He turns to see the purple banded turtle. The one who he so easily took down the first time.

"Did you forget about me?" He challenges. His voice trembles slightly at the end. He swallows hard and prepares himself to get the heck out of here.

Slash grins from ear to ear. "No, never." His deep voice sends chills down Donnie's spine. He lumbers forward, pushing the other three out of his mind. Only the blue one remains a challenge now anyway. This one though, he's uninjured. This will be fun.

"Then come and get me!" Donnie draws his bo staff out as if he is going to fight. He must tread carefully if he wants this to work.

"Donnie!" Leo stares with quickly widening eyes. "What are you doing?" He tries to run fast enough to reach Slash and turn his attention back to him, but he isn't going fast enough. Slash is moving away. No!

"My pleasure." Slash purrs. He jumps forward suddenly, minimizing the distance between them.

Donnie starts and spins around quickly. He sprints and leaps without thinking over the edge. He lands roughly on the fire escape and wobbles for a fraction of a second. Then he rushes forward and jumps the rest of the way down, not stopping for a second.

Slash follows effortlessly. He jumps all the way to the ground in one go. He is right at Donnie's heels. "Coward!" He bellows. Then again, he did always like the chase more than the stealthy attack he had to pull before.

Donnie's heart pounds ruthlessly against his chest. He is sure it will burst any moment. His breathing is erratic at best and his mind is a frenzied mess. A plan – need a plan! Slash's earth shaking footfalls only make him more panicked. His strides are bigger, Donnie knows it, and he is quickly closing the distance between them. What to do? What to do?

Leo runs to the edge and stares after Donnie. He wants to go after him, needs to, but doing it alone is suicidal. He turns back around to his other brothers and moves as fast as he can toward them. "Guys," He urges. He drops down by Raph's side and gently lifts him into a sitting position. "You've got to get up."

He crawls over to where Mikey lays. "Come on," He is even more careful with Mikey. He holds his breath for a moment as he watches his baby brother apprehensively. "Donnie went off on his own and is luring Slash away. We have to follow them."

Mikey groans. His eyes slowly flutter open and he gasps as a sharp pain races through all his limbs. He curls inward and his body shakes with the pain. "I…can't move." He whimpers.

Leo sighs. "Come on Mikey." He supports his brother as he raises them both into a standing position. His legs tremble beneath him as he struggles to keep them standing. "You can do this. Pretend it's the last level of our video game and finding Donnie means we win."

Raph pushes himself to his feet. His shoulder pulses with agonizing pain. Blood drips from it in a slow stream. His vision is blurry and it's hard to walk straight. But Donnie's in trouble. They have to find him. He can't fight Slash alone.

Mikey nods stiffly. He whimpers, but he comes away from Leo and manages to remain standing. "I can do it." He says softly. For Donnie.

Leo nods firmly. He gets a head rush from the movement and feels sick for a moment. Then he recovers. "You ready Raph?"

Raph scoffs. "Like I'm ever not." He clutches his chest despite his confident words.

Leo rolls his eyes. "Alright." He pulls out his t-phone to locate Donnie. Not far. "Let's go!"

Donnie's breathing grows heavier every step he takes. He doesn't know how much longer he can keep going. Even as a ninja speed was not his strong suit. Endurance was one thing, but this was full on sprinting. Still, he pushes. As long as it saves his brothers.

Slash is no more tired than at the start. He closes the distance with every step. With one more push he is right at Donnie's back and a surge of cruel excitement races through him. He rears his fist back and punches Donnie's back with all he has.

Donnie goes flying. He smashes into the wall of the nearby alley, cracking it and his head badly. He slides down the wall and slumps to the ground, his ears ringing. He groans and tries to regain his bearings. Which way was it? Which way lead away from them? He struggles up the wall. He has to keep going.

In that very alley the loud crash startles Alopex awake. She springs to all fours and bristles. She gasps as she sees Donnie slumped against the wall. What is…? She jerks her head around at the sound of another. Who is…? She narrows her eyes and bares her teeth.

Slash lumbers forward. He has no regard for the strange fox just to the side. He focuses his cold gaze on Donnie as the turtle tries to stand despite the disorientating blow. "See?" He booms. "It's no challenge to catch you, techno geek."

Donnie might have been hurt at any other moment – knowing it meant Raph must have called him that at some point or another. But right now he only focuses on a means of escape. And right now Slash is blocking the only one. His breathing comes shallow as he braces against the wall.

Slash rears his fist back and strikes hard.

Donnie can't withstand it. He crashes back and skids across the dirt. He coughs terribly, blood spiting up and trickling from his mouth.

Slash lets out a deep laugh. "No challenge at all.

Alopex gasps and terror twists her face. Her fury rises quickly afterward and she thrusts herself up on her feet. She doesn't wait. She sprints forward and lands a hard kick on Slash.

Slash hits the wall and rips a whole through to the other side. He falls down among the rubble and is left with jarring confusion. He stares blankly for a moment, then his anger strikes with a vengeance. He gnashes his teeth and narrows his eyes as he pushes himself to his feet.

Alopex immediately forgets the large creature. She rushes to Donnie and drops down by his side. "Donnie," Her voice holds a faint tremor. "Are you alright?" She lifts him up carefully.

Donnie does not miss the strange note to her tone. He is both confused and flattered and he smiles despite himself. "You worried?" He half laughs.

Alopex scowls. "You just got knocked senseless!" She has the right mind to smack him for being a smart aleck. "And you're bleeding. Of course I am!" She looks him over to be sure she hasn't missed any other injuries.

Donnie sucks in a sharp breath as Slash reemerges from the hole. "Alopex," He grabs desperately onto her fur. "You have to be careful. Slash – he's extremely dangerous. You need to just run. Hurry!"

Alopex jerks her head around, following his gaze. She bares her teeth and growls faintly. "No way." She rests him against the wall and rises slowly. "If he's really that dangerous then there's no way I'm leaving you alone." She clenches her fists and raises them. "I'll protect you."

"Alopex!" Donnie reaches uselessly toward her. "Don't!"

Slash roars. "Get out of the way meddlesome fox." He curls his fingers inward into fists.

"Not on your life." She hisses.

Slash screams and charges. He runs with a fist up and ready to plow her through with.

Alopex leap nimbly over him and delivers a kick to his head. She lands fluidly on the other side and quickly makes her way back around to his front, between him and Donnie.

Slash is thrown forward and his face pile drives in the dirt. He gets a mouthful and his fury skyrockets. He roars and scrambles up. He strikes in a breath and rips his claws across Alopex's face.

Alopex yelps and draws back. Blood drips from the three cuts down her face. Her lips curl back and she flashes her razor sharp teeth. She extends her claws and lashes out in the next instant. She draws blood once, twice, three times.

Slash draws back each time, but she only advances farther. He quivers with rage and punches out. He hooks her jaw and slams her face into the wall. It may not be one of the turtles, but it is a beautiful sight to behold and he gets just as much of a rush.

Alopex crashes through the wall and hits the ground. She blacks out for an instant, but only an instant. Life returns to her world and her mind finds its grip on the situation. She picks herself up, but she does not rise to two feet. No. Her eyes burn with blinding rage and she finally loses it.

Her animal instincts drive her and she snarls viciously as she leaps up at Slash. She opens her jaw and sinks her teeth deep into Slash's arm. Her bite draws blood and the warm substance stains her teeth.

Slash jerks back and swings his arm around to slam her into the wall again.

Alopex twists herself up and lets go just in time to avoid the collision. She lands brilliantly on her four feet and launches into a dizzying circle around Slash. She goes around and around, not showing any sign of stopping.

Slash struggles to follow her. Every time he turns she is already at his other side. He screams and slams his fists down into the dirt before him, hoping to land a blow. He misses by a mile. Only the earth gives under his heavy hand.

Alopex makes another full circle and then she springs up. She pushes herself high enough to grab onto his shoulders and she twists her head around to bite down mercilessly into his neck. She hits a vital vein and blood flies. It gushes into her mouth and fills it with the warm liquid.

Slash panics now. He slams himself back against the wall with the hope of smashing her between him and the wall. He is so frenzied though that he can not hit it right. He bucks and twists and grabs, but she has him good.

Alopex tears viciously into his flesh. She doesn't stop even as his struggles die down. She clamps her jaw at the back of his neck instead.

Donnie can do nothing but stare. He watches agape as Alopex reverts to her animalistic state. She doesn't even seem to remember what she is fighting for – only that she is fighting to win. Donnie wants to tell her to stop, that it is over. But his throat is tight and voice gone from him. Alopex…it's over…please.

It is then that Leo, Raph, and Mikey show up. "W-What?" Leo gasps. He throws his arms out and stops the other two.

Slash has worked his way out from the alley and is thrashing in the streets. He only has a little left in him and in the next instant he falls forward, weak from blood loss.

Still, Alopex does not relent. She holds him there, his blood tingling against her tongue. Her eyes dart up as she senses another presence and she dully focuses on the trio. These…they are like Donnie. Donnie…where is Donnie?

Raph's face contorts in shock. Slowly it changes to fear. "Spike!" He cries. What is this thing on top of Spike!?

Spike looks up through half lidded eyes. He meets Raph's panicked gaze and for a moment the old him shines through. He quivers faintly and reaches out desperately for his best friend. "Raph…" He wheezes. "Help…"

Raph can't help it. Despite everything, despite how much he shouldn't care, he does care. He shakes fiercely in quickly building anger and screams, "Get off of him! You mangy mutt!" Raph raises his sais and prepares to attack the thing.

Donnie sucks in a sharp breath. No! No! He opens his mouth to protest, but no words come out. He struggles up. He has to protect her.

Alopex releases Slash at the last moment. Her golden eyes glow fiercely and she growls viciously through her sharp teeth. Blood drips from her mouth as she stands over Slash and gives one last passing look to each of them. Then she turns sharply and scampers away.

"Spike!" Raph hurries over to his old friend. There's no reason for him to be stupid, no reason but nostalgia. He bends down and looks through tear filled eyes at Slash. "Spike…"

"Get away…" Slash says weakly.

"W-What?" Raph blinks twice. He wipes at his watery eyes.

"I said. Get away." He glares up at Raph. "I'll heal fine. But when I do…I'll only hurt you again. So go." He clenches his fists threateningly. "Get away!"

Raph flinches, but he does not protest. He nods stiffly. His lips turn down as he stands slowly. There really are more important things to worry about anyway. So with a final look he follows the others into the alley where Donnie lays.

"Donnie!" Mikey manages a little enthusiasm despite his terrible injuries. He sinks down by his brother and looks him in the eye. "You ok?" He holds his breath. Everyone else was punished severely. At least let one of them make it out ok.

"Yeah…" Donnie says distractedly. "I…I'm fine…" He cringes as a particularly painful jolt of pain pulses from his head. He needs medical attention. They all do. This is no time to be thinking and worrying about her. And yet…that look in her eye. The way she acted so viciously…it's terribly off-putting.

Leo leans heavily on the wall, farthest from Donnie. He looks hard at his brother, but he doesn't say a word. He runs through all the possibilities in his head.

Raph shows up in the next instant and speaks Leo's mind. "What the hell was that?" He fixes his gaze on Donnie. He breathes heavily in and out. His patience runs thin.

Donnie shifts his gaze to Raph. Thankfully the blood loss decreases the severity of his reactions. Otherwise he knows he would have been beyond panicked and desperately grasping for excuses. But now, his mind so foggy, Donnie comes to an easy conclusion. "I have no idea." He shakes his head weakly. "It just…showed up out of nowhere."

Leo presses his lips into a thin line. He isn't too sure about that. His nose is itching again and he isn't even close to Donnie. And whatever that was, it was no dog. So if he starts sneezing again, even if he doesn't really, it means that is what he keeps getting a whiff of around Donnie. Donnie knows that thing. Whatever it was.

Mikey glances fervently back and forth between the fallen Slash and Donnie. "Guys," He coughs terribly. "We…we should go." Fear snakes its way up through him. "Please?"

Raph follows Mikey's gaze and grits hit teeth. Slash will be better in no time. He can withstand more and more than likely heal faster than them. Mikey is right. So he accepts Donnie's answer at face value. "Alright," He limps toward Donnie and holds out his hands to both his brothers. "We can talk about his mess later."

Donnie sighs, but it is inaudible. He reaches out and takes Raph's hand with pleasure. In the end though he's the one that is supporting Raph's weight as they struggle back to the lair. Leo helps Mikey along and the four find their way back to the lair without further incident. None of them even remember the fact that they didn't investigate the robberies. They are just happy to be back in one piece. Again it was just too close a call.

More than anything though Donnie prays for a miracle. He prays that his brothers will forget about the strange creature of the night and leave him a little longer to keep her hidden. He really needs it now too, with the way she acted tonight. It's just all wrong. And he has to find out why.

So what did you think? I was really excited to fit Slash in here even though it will probably break canon at some point. Seriously, if Slash never shows up in the show again I will be extremely disappointed. And I know a lot of people are hoping Slash eventually becomes good but quite honestly I don't want that. Like at all. Glimmers of his old self like near the end of this is ok, but I don't want him to stop trying to kill the turtles.

Also I feel it's ok to update the summary now. It shouldn't be too spoilery. Please review!