A/N: This is my first Supernatural fanfiction. As written in the summary it will be kind of like the series, I hope ;) New demon and new problems in every chapter, but of cause it will have a basic line.

Tiana is the daughter of Lucifer, she seeks out the Winchester boys to make them help her stop the apocalypse. To prove to them that she's not like her father or his creations she safes Cas from the madness he took from Sam. Now they boys are back together, and sure they have some issues to discus. In all that Tiana struggles to get the boys to believe her innocent, and together they start hunt down every monster and demon they pass along their way. But the boys have their doubt; after all she's half angel, half demon.

Chapter 1: I'm Nothing Like Them!

The rain lazily made its way down the outside of the dirty window, in the small town, long-forgotten-by- time-motel. Dean was lying on the bed trying to ignore the sound of the thunder in the distance. He had had that dream. The dream had been hunting him for quite some time now. A dream about old times, when he, Sam, Cas and Bobby still hunted together, like a family they stuck together. Well not anymore. Bobby was dead, which still hurt every time reality reminded him. Cas was no longer the powerful, goodhearted angel he knew. Dean didn't even know who the angel was anymore. Though he should be pissed off at Cas for turning evil, or well, making the wrong choice sounded better, Dean couldn't find the right reason for hating the angel. When it came down to it, Castiel did sacrifice himself to safe them, again. No Cas was never evil, just lost. Still Dean had a hard time forgive Cas for what he did. He knew he was probably just being selfish, it wasn't like Dean himself was an "angel". In the dark he smiled sarcastic to himself by the expression. He tortured helpless souls in hell, what Cas did, at least he did it for a good cause, or he thought he did, at first. Yes mistakes had been made on both sites, and perhaps if Sam and himself hadn't been so caught up in their own problems, they would have noticed the troubles the angel was dealing with. But no, Sam and Dean always came first, Cas never complained, and if he did he was overheard. Dean felt sickness overwhelm him, how could anyone call themselves friends if they weren't even there for each other. He told the angel that he would die for him, but he couldn't even get the time to hear him out when he begged them to listen. Like with those two boys in the prison, Dean and Sam ignored Cas who practically begged them for help, but once again, the angel was ignored. Dean turned in the bed, he could discern Sams sleeping figure on the bed in front of the curtainless window. Dean sighed. Yes he got his brother back once more, and of cause that meant everything to him, but he did miss Cas, more that he would ever admit actually. Not in a freaky romantic way, but he missed his best friend. How Cas made him smile just by being Cas. Well all that was long gone. Castiel as Dean knew him died when he went God-ish. Nothing would ever be the same again. Mostly because Cas now was locked up in a mental hospital, unable to escape his own tortured mind. This truly did hurt, knowing his best friend was rotten up, and Dean was completely helpless against it. Of cause he told Sam that he didn't give a darn about the mad feather full, idiot, but that was a lie. A lie he even tried to convince himself about, it just wasn't working, and though Sam played along, Dean knew he didn't buy it either. Anyway what's done was done; nothing could change that no matter how he prayed.

Suddenly a dark shadow went past the window, just in a glimpse of an eye, and then it was gone. Dean rose to his elbow and grabbed the gun which was always in reach under the bed. It fit his hand perfectly, like it was a part of him. "Sammy?" he whispered looking at his sleeping brother in the dark. No response. "Sam!" he repeated, this time a bit louder, however the effect remained the same. Dean rolled his eyes, sat up and with his free hand threw the pillow on his bed, in the head of his younger brother.

Sam grunted irritated and slowly opened his eyes just as a slight, almost mute, knock on the door sounded. Dean got up and made a cast with his head against the door. Sam immediately sat up, just like if Dean had thrown an invincible ice cube down his back. He also got a grip on his pistol on the nightstand beside him. They slowly and carefully walked towards the door. Dean placed his hand on the doorknob. "Who's there?" He spoke in a powerful voice, not removing his eyes from the wooden door in front of him.

"Please help me in! I'm in trouble," a frightened female voice called from the other site of the door. The brothers exchanged looks, before Dean slowly unlocked the door, never letting the gun down.

He barely got to open the door before a girl around their age stumbled into the room. Her long golden hair was wet caused by the still insisting rain, and her brown eyes were big and scared. "Thank you so much!" She said and first now looked at the guns. "What the…?" She stumbled a few steps backwards locking her eyes on the firearm. Both boys immediately let the guns fall along their side.

"Sorry about that," Dean spoke, sending the scared girl his best innocent smile, "you know, one can never be too careful." He turned on the light. The room was small, and old. The carpet was red and filled with dirt and spots from some of the former guests. The wallpaper was also filed with dirt and some places it just hang loose from the wall. That was what you could get when you lived a life as a hunter.

She finally looked back up at the two guys. "So you need help?" Sam said trying to break the awkward situation. "What happened?" He sent her a concerned look, a look Dean always envying him. That always seemed to get to through to the ladies.

The girl looked out the window. "Something's after me," she said just above a whisper.

"Something?" Dean faked a laugh, as if he had no idea of what kind of creatures lured in the dark. "Don't you mean someone darling?" spoke Dean following her stair.

She sent him a hard look. "No, not when I say something!" She hissed. "Listen, you're the Winchester boys right?" Her look got milder as she looked from one of them to the other.

"It depends on who's asking?" Dean said now raising his gun a bit once more. Sam stood still, he didn't quit know however he should raise the gun at her, or hear her out.

Either she didn't notice, or she didn't care about the guns anymore, cause in two quick steps she stood in front of Dean, she kissed him gently on the cheek then turned to Sam only to repeat it on him.

The boys looked alarmed on each other, then back at the girl. "I've been waiting for this moment for so long," she sighed and sat down on the empty bed Dean just left minutes ago. She cast a look around the small room.

Dean smirked. "Well if you wanted me so bad you could just have asked."

Sam rolled his eyes behind his brothers back; the girl just sent him a confused look, "What?" she said looking at him in disbelief.

Dean cleared his throat and bit his lower lip, casting a look over his shoulder to his brother. "Can't blame me for trying" he parroted. Sam shook his head a bit.

"Excuse me for asking," Sam started, holding a tight grip on his gun, "but who are you?"

The girl rolled her eyes over her own lost manors. "Of cause, I'm sorry. My name is Tiana, I'm in serious need of your help," She looked down and bit her lower lip, like she was ashamed of what she was going to tell them. "I know what I'm going to say, might will freak you out, but you gotta believe me, I'm not trying to harm anyone."

Now both guns were pointing at her again. "Let me change the question," Dean said sending her a suddenly hateful look. "What are you?"

Tianas look got sad and guilty. "I'm the daughter of Lucifer," she said, her voice were shaking hard. Both brothers now looked ready to kill, she threw her hands up in front of herself for protection and closed her eyes, "wait, please, I'm nothing like my father or any other of his creations! I want to use my power for goodness, and I want to help you too!"

"Sure you do!" Dean said sarcastically, "and in a few moments you're going to throw roseleaf and bunnies around right?" His eyes were hard and cold. He'd struggled with enough of her kind, Lucifer, Leviathan, monsters, demons… angels. Every time it ended badly. Like in losing someone dear, his dad, Sam more than once, Linda and Ben, Bobby, Cas. This just had to stop.

Tiana opened her eyes, and looked at them, "just hear me out before you try to kill me? Please?"

"Dean," Sam placed his hand on his brothers gun and sent him a worried look. "Let's just hear what she has to say."

The older brother sent Sam a hard look. "Really, Sam? You trust her? You heard her! She's the daughter of Lucifer! Let's just kill her now and get it over with."

"Dude, I'm not saying that I'll cast myself at her feet or anything," Sam sighed, his older brother always had a habit of kill first, and ask questions later. "Let's just hear what she has to say; maybe it can help us figuring out what the demons are up to." Sam said better knowing.

Dean sent him an irritated look, they did need to figure out what was going on. After the Leviathan broke loose monsters and demons was fighting for power, to get hold of as many souls as possible, no one including the brothers knew what they were up to, if they worked together or separately, and then there was the angels. It seemed like all hell was about to break loose, again, and without Cas to help them, it all seemed like a lot to overcome. "Fine! But I don't like this Sammy." His voice was hard.

"So," Sam said looking doubtful at the girl "you better start talking before I'll change my mind."

Tiana took in a deep breath. "I might be the daughter of Lucifer, but that doesn't make me evil. In fact he himself couldn't turn me into the evil weapon he wanted me to be, so instead he threw me into the purgatory, I've lost count of how many years I've been down there, suffering because of the choice I took, hoping someone could help me out of my misery one way or another. Just as I was about to give in to the dark part inside me, thinking it was my destiny, someone opened the purgatory and I got out. I heard some news, an angel of the Lord, Castiel, had rebelled."

"Yeah, that went great for him," Dean mumbled still impaling her with his look.

"He made a mistake, but I know for a fact that he isn't the only one in your trio who gone dark-side." She sent the brothers a knowing look. "However I also heard that he did what he could to make it up to you, taking Sams "madness" for starters," she said coldly.

"You seem to know a lot huh?" Dean looked her upside down. "You know what? Times up bitch! Tell your daddy to go screw himself!" Dean pointed his gun at the girl, and pulled the trickier before Sam was able to do anything.

However the bullet stopped in front of her head and fell to the ground. "Well that's unfortunate," Dean sent Sam a troubled look and took a few steps away from her.

"I don't know what surprise me the most," Tiana sent him a cold look, "the fact that you thought a bullet could kill me. Or the fact that you even tried to kill me at all." She slowly got up.

"Any bright ideas Sammy?" Dean turned to his brother with a very worried expression. "I think I just pissed her off."

Sam looked like Dean, troubled, worried, scared. Tiana sighed. "I'm not going to hurt you guys, if I wanted you dead you'd be nothing more than a mess on the floor right now."

Sam and Dean exchanged looks. "So what do you want?" Sam asked trying to look away from the fact that Dean just tried to kill her.

"To live," she replied gently. "The demons are after me, because I am the key to melt heaven and hell together here on earth. The angels are after me for the same reason; everyone wants me dead, except me." Her voice was filled with sadness. "I don't want this world to be destroyed, and I don't want to die either, to prove myself to you, I'm willing to safe your angel buddy from his madness."

Suddenly Sam took a step closer to her and held his hand in front of himself as he talked. "So you say that you can heal Cas?" His voice sounded interested and hopeful.

She smiled. "Yes, I can, as he did, turn it around so I get the madness instead of him."

"Okay, so you don't want to die, but you're willing to take Cas' place on a maniac institution?" Dean sent her a doubtful look. "I'm sorry but I'm not following here. What's in it for you?"

She sighed. "I didn't say that I would take his place, only his madness, however I have an advantage that Castiel didn't; I lived my whole life in hell during Lucifers government. I can handle whatever torture he has for me."

"Still" Dean said, "That didn't reply my other question, what's in it for you?"

She sent him a sad look, like she was trying to read him. "You really think I will turn and bite you. What I hope to gain by healing your friend is a bit of trust, or at least your help so I can survive."

Deans look was still hard as stone. "What makes you think that you deserve to live?"

"What makes you think that I don't?" Her question hangs in the air for some times. She had this special glow over her, not something that people would be able to see, but almost like she was too clean, to host any evil at all. "Listen, if I don't succeeds saving Castiel, I'll be mad and lay there drooling on the floor, but at least you have your friend back, if I do succeeds we take it from there, okay? It's a win-win situation for you."

"Well you seem pretty strong to me," Dean said awkwardly and raised a brow, "so why do you need our help? Why do you want to safe Cas? And how do you even know about him and his state of mind?"

"I am strong, but not as strong as many of the demons who are hunting me, you see, as long as I don't use my powers for evil, I'm weakened. My powers were created for evil, not for good. I want to safe Castiel, because after all he was the one who safe me from purgatory. I feel like I owe him that. I know about him, because I'm me, and I know that kind of stuff."

Dean shook his head and faked a smile, "now that's just touching."

"Listen, I don't care what you think, just let me help you, let me prove to you that I'm here to help." She sighed. "You helped creatures who were different before, vampires, werewolfs, why won't you help me?"

"Dean, can I talk to you in private for a second?" Sam looked at his brother, who sent the girl another weird look, nodded and followed. They walked away from Tiana into the small corridor. With their jackets hanging on the wall, the room almost wasn't big enough for both of them.

"What are we going to do about this?" Sam looked at his brother.

"We find a way to kill that thing.." Dean started but was caught off by Sam

"That wasn't what I meant Dean,"

Dean sent him a puzzled look. "Then what do you mean Sammy?" His voice had a bit anger in it witch Sam ignored.

"She cans safe Cas," Sam said, still dealing with the guilt for letting Castiel take over his madness.

Now Dean got a troubled look at his face, "Sam no! Whatever that thing is, it's not the answer to our problems! We agreed to not make any other pact with demons!"

"But Dean it's Cas, he saved us so many times I lost count, he would die for us, and we said that we would do the same for him."

"Sam, that was before…" Dean started and looked down.

"It doesn't matter what he became, in the end he made it right, and that's what counts." Sams suddenly got a sad look at his face, "I just can't leave him like that Dean, not when we may have a chance to safe him, please? Besides his the only one we know who can figure out what's going on."

"So you want us to just trust her? What if she tries anything, what if she goes totally Ruby on us and only want us to tell where Cas is so that she can kill him?" Dean took a hand to his forehead in frustration, "Sam, we can't make a deal with a demon, we just can't"

"Well good news for you guys," Tiana walked out in the small corridor, "I'm no demon, and I don't want to make you any deal. In fact I'm also half angel, you seem to forget that my father Lucifer is an angel, not a demon. To be completely honest with you, I'm the angel of hell, and I can be very dangerous if I choose to, which I don't. " Another sigh escaped her lips. "If you want to kill me use an angel knife like the ones that kills angels. There, I showed you trust, please do the same to me."

Dean cleared this throat, once again feeling the awkward silence. "You know what? Fine! Safe Cas, prove us wrong, but I warn you" his eyes was cold and his mouth was nothing but a small string, "if you tries anything, we will kill you!"

The older brother looked at Sam and shook his head. He was scared to death that the demon-angel, whatever she was, would might kill Cas instead of helping him, after all he still was a friend, also when Dean wouldn't admit it. But Sam was right. Without Cas they were lost, they didn't have anyone to turn to, no Bobby to ask for help. This was their best, and maybe only shot to make Cas "normal." Hopefully he wouldn't snap again. Somewhere inside himself Dean knew that Cas wouldn't. He wasn't himself at that time. He'd always been there for them, and now it was time to return that favor. Then Dean grabbed his jacket and took the car keys in his hands looking from Tiana to Sam. "Don't make me change my mind."

"I won't, " She sent him a shy smile.

Dean threw himself into the black impala and Sam sat down on the empty seat beside him. Tiana sat behind Dean. "Cool car." She said looking at him in the rearview mirror.

"Just shut up," he mumbled irritated.

Sam sighed and looked out the side window, not wanting to argue with his brother.

Tiana rolled her eyes, "aren't you happy Mr. Sunshine," she mumbled and also cast a look out the window beside her.

The black impala disappeared into the night leaving the old motel in the bag of memories.

A/N: That's it for now, this chapter is really short for what to come, but I have to warm up to you guys right? ;) Please tell me what you think, do I have enough details? Are Dean and Sam in character? And if anyone would like to be my betareader please let me know! :D