A completely AU fic, about an ex-companion turned Assassin, it's a bit crazy. I wrote this ages ago, sorry if it's really bad.

Disclaimer: I don't own Doctor who. I do however own a remote control Dalek, which I will take over the world with. Until then however only own Ruby, everything else belongs to the BBC.

Companion

Two weeks, watching, waiting for him. The Doctor, following his every move, his companion; Rose a beauty if ever I saw one, but a life is a life, and a job was always a job.

"Doctor hurry!" her voice was quick panicked, but he paused scanning the area, I should have know that he would notice I was tailing them sooner or later. I hopped it would be later though.

As Rose hits the doors of the TARDIS begging entrance I can't help but smirk, humans are pathetic. The Doctor waved his hand and the doors opened the lock removed, Rose glared at him from her position on floor, she had landed in an unceremonious heap on the floor, he helps her to her feet still looking around as he drags her inside. I nip though the open TARDIS door praying he doesn't have a cloaking devise detector on board, I smile as I look down, I'm still invisible and no alarms have gone off.

Rose is panting now, clutching her Doctor, she looks terrified, she should be.

"Doctor…" her voice is small, weak, pathetic. She is unimportant, I may just kill her for the sake of it.

"Rose?" he looks at her worried, so much compassion for such a weak being. He will pay if not only for that.

"What's going on, why did we run?" she was confused and I can't help but cover my mouth to stifle the laugh that begs to escape.

"There's something…or someone…following us Rose…" he pauses getting to his feet, I feel proud that I have put fear into both of the last of the, Time Lord's hearts. I can hear them beating quicker, my acute sense of hearing zoning in on their thoughts.

'No, no not her, not her…it can't be not again' pulling out I smile, he knows it's me. He let me down. I can smell his fear now, radiating from him as he thinks my name; 'Ruby' I grin, he remembers.

I then look to the human now getting up from the floor, tuning into her brain is much easier humans always were easy; 'What isn't he telling me? I can't be left out' I'm pulled out of her head by his voice.

"Rose, what ever you do don't think, not at least of anything important!" he is scared now. Excellent. Ruined my fun now though.

I contemplate revealing myself but then again what good would that do? I pace around them, my footsteps unheard by both Rose and her precious Doctor, I don't envy her, he'll break her just like he did me.

He had a different face then, but I would know his scent from anywhere, there are things you learn about a person when you get as close as I did. Worlds wiped out as if they never existed, in front of my very eyes, I saw it all. I was once like Rose, holding the adoration of the Doctor, holding everything. Sadly men, or maybe it was just this male in particular, don't stick around if they think you're dead.

I whisper in his ear; "Not quite forgotten!" he winces, I smile moving away quickly.

I could kill him right now, dead, watch her mourn, or I could kill her and watch him blame himself and seek me to kill.

The choice is so tempting to kill her, just to watch the agony on his face, he loves this one. I can see it in those dark brown eyes. He never loved me, never treated me like he treats her. Maybe I do wish that he felt like that about me.

"Show yourself Ruby!" he yells to me, I smile as I turn in a circle appearing right under his nose, he jumps back and I hear Rose gasp.

"What's the matter Doctor you look like you've seen a ghost!" I cackle as he frowns that deep knowing frown of his.

"You by rights should be one…" he whispers.

I smirk as I walk over to Rose, she shrinks back, I raise an eyebrow; "Not the bravest…" I spin on my heal.

"Honey I'm home!" I laugh.

He frowns again; "I'm so sorry…" he pauses and I laugh.

"You always were one for apologies…one thing about you I always hated." I look him up and down measuring his reaction. I wanted to make this kill so badly, I pace the TARDIS, I know now why she hadn't alerted him to my being there, she didn't think I would have the guts to kill him, to leave him for dead, I should as it's just what he did to me.

I watch as he places his hands in the pockets of his pinstriped suit, something I have noticed that he does often now, he's changed.

"You miss me?" I ask, turning my back on him.

I feel his heartbeats slow slightly, skipping a beat, both of them.

"Of course…" he whispers.

"Don't…you and I both know she's my replacement!" I point at Rose coldly, I feel the dead weight of my gun against my hip, I could do it now, pull the trigger, kill him. Kill them both.

"I came here to get even…" why am I telling him, he'll talk me out of it, make me feel guilty, he always does.

"You have the right to!" I freeze damn him. That air of doubt that I will, he's taunting me. Coaxing me betting me that I can't kill him.

I can though of course I can, he did this to me, I'll be saving Rose and who ever his next companion is, for the pain of having to let him go, having to say good bye. He leaves you behind rather than watching you grow old, he wont commit he'll just walk away, he will I know it, I've seem him do it so many times, I wont let it happen to that next poor soul to fall under is grasp.

"You can't!" I hear Rose cry, desperate and clear.

"I can!" I say back to her defiantly. "Do you really think he's going to be around forever? Your Doctor protector of worlds, saviour? You know nothing. He does all this to save his own conscience nothing more. He still feels guilty after the Time War!" I spit 'Time War' out as if it were a filthy word.

I accept that I wont get him back, I accept that I wont be able to kill him, he knows I can't and now I too know that I can't. It would be too hard. He is so perfect. She is right for him. Maybe he wont break her heart. Maybe. Something more sinister than revenge hangs over the Doctor and Rose, I can feel it looming in the air. Their impending doom? It couldn't be?

I turn to look back at him, his face so different he regenerated, 10th now I would guess…they get younger each time, but your love for each face never wavers, I miss that manic grin. He still has a daft one, but it's not the same, my Doctor is gone. He has been for a very long time. I can tell he's trying to read my mind, he always used to try. Failed every time of course, but he still tried.

The perfect smile, perfect mouth, smaller ears, brown hair and brown eyes; "I missed you…" I whisper, feeling a sting as tears well up in my eyes.

I know I shouldn't be crying, I'm here to kill him not cry all over him. His eyes are dark, he's thinking.

"I could still do it you know…" I say my voice cold, he looks up.

"But you wont though will you?!" he is unsure, but then again, so am I. I could have killed him 10 times over by now, it's my profession it's what I'm good at. "I took you with me to get you away from all that!" he says taking a step towards me, he's angry now I can feel it.

"Well you failed. You failed me and you failed yourself…you left me to die. Don't you ever think I'll just forget that!" I watch as he shrinks away, of course he feels guilty, of course he feels responsible it's his fault, all his fault.

"I've seen things you wouldn't even be able to begin to imagine…you know I've touched death, it was cold and unforgiving hatful and it was…it was…" I see tears in his eyes, the Doctor is crying…he doesn't cry, he can't it's…

Rose is by his side now, she's taken his hand, it's clear that she hasn't been listening to a word that I've been saying, she's such a stupid girl, thinks that he'll be with her forever, that thought allows me to feel that chill again, the one of deaths grasp it is my time, as it will soon be hers, poor child, poor innocent child. Death is calling, time to go Ruby.

"I'm sorry!" I whisper as I pull the gun out.

"NO!" his shout is deafening but not as loud as the bang.

My limp body slides onto the floor, blood pouring from an unforgiving wound. Even in death I know that he's crying even more now, cowering over my body, a self proclaimed cowered.

"No Ruby no…" he whines begging me to come back he looks to the TARDIS ceiling but she wont save me; "HELP HER!" he screams desperation emanating from his every pour. Rose is scared, she has never seen him like this, he will never be the same. "I'm sorry, I'm so so sorry!" he whispers as my life force seeps away. He doesn't need to be sorry. I had decided long ago it was him or me. I could never kill him, so I was all that was left.

Darkness filled me, I was long gone, he knew this the moment my limp body hit the grill of the TARDIS floor, he was still saying his; 'sorrys' moments later, Rose stunned into silence, she looked as though she wanted to throw up, he would have to clean up my blood soon or she would empty her stomach contents onto the floor.

-I am sorry- The last thoughts of a dying soul.

A/N: I know it was rather bad. REVIEW please make me feel slightly better about it. No flames please.