A/n: Been super busy lately as it's Chinese New Year in my country. I just barely had time to time to do up this chapter so apologies for any errors and its length. I promise things will get more interesting in the next chapter.

As usual, thanks to my reviewers (you know who you are)

Chapter 4

After Fury left them, Bruce immediately ambushed the newcomer, his curiosity perked by everything she said earlier about the existence of another world. Abandoning his initial ill-feelings of her, he walked over to her, catching her attention by clearing his throat.

"Miss Pierce?"

Katherine turned her attention away from Steve and Tony who had started bickering over the attack on the hotel and glanced at the doctor. "Doctor Banner, right?

"Yes." he smiled, offering her his hand and when they shook, he mildly noted how below normal human temperature her hand felt. "What you said earlier, that was fascinating. I never knew and for someone as young as you to be such an expert on it…"

"Ah, yes." she pursed her lips briefly. "It runs in the family. Quite a curse and a blessing actually."

He chuckled. "I wish I could say the same about my situation." he stopped when he noticed her studying him closely. "What is it?"

"Nothing. I am just trying to figure out which one are you."

"Which one?" he blinked then it clicked that she was trying to guess his role in the Avengers and he let out a low laugh. "Boy, Fury really didn't brief you on us, did he?"

"Sadly no." she said, making a mental note to throw a book or something at the director. "He decided it would be more fun to let me guess my way through."

"I know the feeling."

"So, let me see…" she cocked her head as she took in his entire statue. "Steve is Captain A and Jackass is Ironman. That just leaves the God of Lightning and the big green guy… You don't strike me as the 'Shakespearean-in-the-park' type. What?"

Bruce stifled his laugh. "You have no idea how much you sound like Tony."

She blanched visibly. "Please don't make me puke. Now where was I? So…" her eyes widened a faction as by deduction and hints from her instincts, it dawned upon her. "Big green?" she asked.

"Yup." Bruce answered sheepishly, already anticipating her running to the others for safety. "But it only happens when I get mad or upset."

"Huh." That explained her instincts going into overdrive and she stored this information away. She shrugged. "Remind me never to piss you off then."

"Yeah, that would be wise." he agreed, surprised that she wasn't the least bit afraid of him as they glanced at the two men still locked in a heated verbal battle. Clint was trying to mediate between them and looked as though he could just knock them out.

"Is this normal?" Katherine asked, wondering how Tony could claim to be Steve's friend when they were currently on the verge to killing each other.

"Unfortunately, yes." Bruce muttered regrettably.

"It was supposed to be a simple extraction mission." Tony was arguing. "I was the best person for the job."

"Why? Because you're so charming?" Steve retorted.

"Why, yes. That seems to be the best explanation of why Fury picked me over you." the billionaire quipped. "I got her here, didn't I?"

"Well…," Katherine drawled, halting the argument momentarily. "Technically, Stark, you did drug me to get me here."

Steve whirled on the other man, ready to go another bout only to have the dark-haired female step between them, her hands firmly planted on their chests and pushed them apart. Tony and Steve shared a mildly surprised look. She was stronger than she looked.

"Will the both of you knock it off?" she admonished, unable to believe that they were part of the team that saved the world. "Geez, if you guys were any more testosterone driven, you are in danger of getting yourself pregnant."

There was brief moment of stunned silence as the men digested what she just said before snickers and barely suppressed laughter from Client and Bruce broke the quietness, elevating the terse situation effectively. Satisfied that both men had stopped acting like children in a playground, Katherine leaned up against the table.

"So…what's the deal with Red?"

Before any of them could answer her question, Clint pressed his earpiece, listening to something someone was saying on the other end. "We'll be right there, boss." He turned the rest. "Director Fury wants us in the lab now. He has something to show us, especially you Miss Pierce."

They quickly filled out of the room with Tony in the lead. Katherine followed from behind, her eyes taking in the structure as they passed through several hallways. Several agents respectably allowed the team to pass and she couldn't help but notice the curious looks they gave her.

"Gentlemen." Fury greeted when they reached the lab. "Miss Pierce, it looks like your consultation hours starts now."

Katherine stepped in for a closer look, glancing to her side when she sensed eyes on her. Natasha stood beside an elderly man who has yet to look up from his specimen on the table but her eyes watched the other female warily.

"What are those?" Bruce asked staring at the dead woman on the table. She looked human even in death but he couldn't shake the feeling there was something familiar about her. The other dead body however was a different thing altogether.

"These are the bodies we extracted from the Plaza." Fury explained, pulling one of the panel over to show them their findings. "The first body is one you are all quite familiar with."

Tony started fiddling with the images and numbers on the screen. His frown deepened and everyone knew if Tony was frowning, it wasn't a good sign. "Very familiar indeed." he muttered gravely as the internal exoskeleton came on screen. "Right. Here's my question. Why does a Chitauri look like a human?"

"Hold your questions until you see this one." Fury beckoned for them to approach the next body.

Doctor Selvig looked positively excited as he prodded at the elongated limbs that were covered in coarse grey hair. "The arms and legs are still growing! It's like the creature is reverting back to its original form. And its facial features…"

"Hideous." Tony shuddered staring at the snort and muzzle that was closer to a beast than man. "He looked much better last night."

"Well, given that he's dead…" Bruce pointed out.

Steve glanced at Katherine who approached the body cautiously, noticing how her dark eyes were narrowed. "Are you okay?"

"Miss Pierce." Fury called. "What is your expert opinion?"

"That's a werewolf." she muttered. "Lycans with the ability to take on human form. They can only transform to their natural state under the full moon but even in human form, they're dangerously powerful."

"Hm. Can't be that powerful." Clint commented. "Since Tony managed to take him down."

Katherine tensed as she continued. "Werewolves are almost invulnerable with their accelerated healing abilities. Silver can weaken them while a straight shot to the heart will kill them. Other than that, decapitation works just as well. But…" she studied the wound closely, puzzled that it hasn't recovered. "This is the first time I've seen a werewolf taken down so easily."

Natasha scoffed. "If you call that easy."

"Hey, I think I deserve a bit of credit." Tony said.

"They're usually tougher than this." Katherine muttered, thinking to herself. "And they don't act outside of their packs. Werewolves are pack animals, capable of working only with their own."

"So the real questions are why is the werewolf working with a Chitauri and does this have something to do with the Chitauri's new ability to take on human form?" Natasha said. She hated to say it but the information the other female had just provided them was useful. "Because if it does…then we're in trouble."

"Miss Pierce." Katherine was beginning to hate the way Fury addressed her every time. "Perhaps it was time you tell us who is after you."

All eyes turned to her and she signed nonchalantly. "Oh, joy… This will be…fun."

~.~

The meeting place was not the best of places but it served its purpose in terms of secrecy. The old sewage factory downtown had long past its usefulness and had been forgotten and abandoned by the city. But to the creatures that lurked in the dark, it served them well. This morning two heavy tinted cars drove into the covered building, parking and a group of dark cladded people stepped out. In lead was a tall blonde female with piercing green eyes.

Keeping to the shadows she strode up to the figure that awaited them. In appearance the male seemed human with his smart casual appearance and handsome features but she knew better. She could smell the alien in him.

"Zarkis, I've received word that we have failed to capture Katherine and that she is now in the custody of SHIELD and in effect, the Avengers." she said with a frown.

"Had the assassin and Iron Man not been there, we would have had her by now. However that was merely a test mission to observe our…unique partnership." one of the men said calmly. "These human bodies limit our capabilities."

"But it allows you to sustain yourself independently and keeps you hidden from your enemies." the blonde reminded them. "Which is what you need if Thanos is to launch a full assault on earth."

"But first we must remove the SHIELD and the Avengers. As the God of Mischief, Loki has proven in his attempt, these humans are not to be underestimated."

"Neither are my forces." she nodded at the group behind her. "Because at the end of the day, these humans are merely humans. They can be killed."

"Meet your end of the bargain and Thanos will abide by his end. The earth will be returned once more to the vampires and werewolves once Thanos has enslaved the human race." the disguised Chitauri said. "And you shall be its queen."

~.~

It was back to the meeting room for them, leaving Selvig to continue studying the alien. This time the attention was solely on Katherine as she took her time piecing her thoughts together. Steve studied her expression and it worried him a little. In the short time he had known her – 24 hours to be precise – he has never seen her look so...torn and frightened.

"Director, maybe we should do this later." he suggested turning to appeal to Fury. "You know, until once Miss Pierce is ready."

"I am ready." She said, looking at the group and at Steve in particular. She inhaled deeply, an old human habit of her to claim her nerves. "His name is Klaus. He's a vampire and not just any vampire. He is...the oldest vampire in the world."

Pregnant silence filled the room and taking in their stunned expressions, Katherine continued. "He is the first known vampire to walk the earth and is feared by many in the supernatural world, vampires and werewolves alike."

"And he's after you?" Clint asked in confirmation.

"What did you do to piss him off?" Tony asked non-eloquently.

"I know too much." she answered shortly. "And he wants me silenced."

"Yikes." the inventor muttered.

"How long has he been after you?" Steve asked.

"Um, for as long as I can remember." she answered honestly.

"Is there a way we can stop him?" he continued.

She sighed. "Believe me, if there was a way to kill Klaus, I would have done it by now. As far as I know, no one has ever come close to kill him. But like all of his brethren, Klaus is not immune to vampire weaknesses. Vampires can be killed by long exposures to sunlight but Klaus has acquired a talisman of some sort that protects him from the sun's effects." Here at this point, she noticed Fury staring at her necklace and she knew he was fitting the pieces together. "And contrary to popular belief, garlic and crosses have no effect on vampires much less an Original. However vervain has been known to weaken them tremendously. Having vervain on you or in you keeps the bad vampires away. And of course, there are three known ways to kill a vampire."

She held up three fingers and counted them down. "One, the traditional wooden stake through the heart. Two, ripping out their heart. And finally three, decapitation."

Clint half-raised a hand. "How can we tell a vampire apart from a normal human? Because you know, we don't want to accidentally go around killing innocent bystanders."

Good question. "You can't." she said. "Well, not immediately anyway."

"That helps." Tony summarised, earning an irritated look from her.

"So Klaus." Surprisingly it was Natasha who interrupted. "Do we have a lead on his whereabouts?"

"Well, I can tell you where he is not and that is New York." Katherine said absent-mindedly. "Klaus is rather recluse and only those in his inner circle know where to find him."

"So our best bet now is to work with what we have and find out why a werewolf was working with a Chitauri." Fury said. "I'll have my agents working on tracking down werewolves in New York and finding out how the Chitauri got in without our knowledge."

"Sir, perhaps we should contact Thor on this. He might have some ideas." Natasha suggested.

Nobody noticed when Katherine visibly blanched when Thor's name was mentioned.

"Our communications portal has yet to be stabilised." Fury said. "But we'll keep trying. You are all dismissed for today but be on standby."

"Aye aye, boss." Tony mocked salute like the man-child he was.

As they began to clear out, Fury turned to Steve and Katherine. "A car is waiting for you two downstairs that will take you to your apartment. I have allocated an expanse account for you, Miss Pierce that will help you with your…requirements as well whatever you need in order to aid Captain Rogers. Your personal belongings have already been taken there."

"How kind of you." she muttered sarcastically.

"I understand our arrangement is a little unorthodox but it is for the best. You'll be safe with Steve." Fury assured her.

Because you need me for what I know, you foolish human, the thought crossed her mind as she smiled. "You know your men best. I am entrusting my wellbeing and life in that of your hands and in that of…Captain America."

As she strutted off after Bruce who didn't seem to mind her company, Fury sighed as he turned to a baffled Steve. "Looks like you got your hands full with this one, Cap."

Was that sympathy in the director's voice? Steve couldn't be sure.

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