Disclaimer: All recognizable characters, items or concepts are the property of their respectful owners.

Back in the day I was a huge Buffy fan, and after I saw several crossovers exploring the idea, I felt like adding my two cents to the crowd. While the idea is not original, I hope that I will be able to put my own twist on it that will keep it interesting to people. With that, I leave you to read and comment on the idea.

Chapter 1

"So, are you guys excited about Halloween tonight?" Xander turned to his friends Buffy and Willow as they walked through the school.

On the outside, these three were just ordinary students of Sunnydale High, but that couldn't have been further from the truth.

Buffy, a short blond girl that looked and acted as a poster girl for a California ditzy blond, was actually the Vampire Slayer, a supernaturally endowed girl that acted as humanity's protector against anything that went bump in the night.

Willow was an excitable red-haired girl with a habit of babbling whenever she got fired up about a topic. She was also one of the smartest students in the school, and had a cute, innocent look about her.

Xander was an average guy with slicked back black hair and laid back attitude. Compared to his friends, he was completely ordinary, but he still strived to contribute to the group he started to call the 'Scoobies' ever since Buffy saved him and Willow from a bunch of vampires.

"I don't know. I was looking forward to a quiet night." Buffy shrugged. Halloween was a night when the forces of darkness took a night off for some reason, and Buffy intended to capitalize on it.

"Ah, Ms. Summers, just the juvenile delinquent I was looking for. I'm sure you have all sorts of unsavory plans for tonight, so allow me to channel that energy to more productive uses." Principal Snyder interrupted them as he held up the sign in sheet for the volunteer escorts for the school children for Halloween.

Buffy protested, but the principal didn't give her much choice. Xander and Willow's smug looks were erased quickly as he handed them a pen as well.

"So, we have to get dressed up and everything?" Buffy protested.

"Snyder said costumes are mandatory." Willow replied.

"And I was so looking forward to staying in tonight. Giles said that Halloween was the one night that the undead stay in." Buffy sighed as they sat down in the cafeteria.

Later that day, the trio met at a new costume store called Ethan's to get something to wear for tonight.

"Anything catch your eye, Buffy?" Willow asked as they were browsing the store.

"Nothing yet. Hey Xander, you find anything?" Buffy turned to him only to find him almost drooling at a set of three costumes.

"Those look interesting." Buffy commented as she examined them.

"Yeah, Jesse and I used to play the game all the time." Xander said with a sad smile as he remembered his best friend. Buffy had been too late to save him, and Jesse had been turned into a vampire.

"We should take them. It will be nice to have matching costumes." Willow grinned. Jesse was her friend as well.

"I can't possibly afford this." Xander protested.

"Perhaps we can make a deal, young man." The owner had walked up to them as they examined the costumes. The man had an ever present slight grin as he stood before them.

"What sort of deal?" Xander turned curiously towards the man.

"Well, you're the first to show interest in these costumes, and I'd hate it to leave such interesting outfits stay unused, so I'll rent them to you for fifteen dollars each." The man grinned.

"I'm afraid I don't have that much…" Xander sighed.

"I'll cover for you. I know how much this means to you." Willow gave him a grin.

"Marvelous. I'll pack them up for you." Ethan grinned and began to remove the costumes from their racks.

"This is hard to move in." Buffy complained as the trio walked down the street to meet their young charges.

"What are you complaining about? How do you think I feel?" Xander was completely encased in his suit; there was not even a patch of skin showing.

"Wow that is so cool." The children were more than a little impressed by their costumes, and they drew stares from a lot of their classmates and adults around the high school.

The trick-or-treating went well, with kids running excitedly all over town, eager to get as much candy as possible.

"Alright, it's almost time go get back. Let's hit a few more houses before we do." Buffy grinned at her group.

A strange feeling began to wash over her as they walked, and she staggered and nearly fell over. She leaned against a fence, and when she stood up, her eyes narrowed in hatred.

"Die, daemon scum." She raised her left hand and leveled the large gun at the nearest monster before her. A glowing ball burst from the gun and slammed into the creature, burning a large hole in its chest.

"Cleanse and purify." Her right hand swung to the side, and the sword in her hand cut through another monster. Seeing the threat, the monsters grouped together and charged her en masse.

"Be gone, in the Emperor's name." Her eyes glowed and her right hand began to emit sparks of energy. A shockwave hit the group of monsters and scattered them across the street.

"This is Inquisitor Selena Vandis to all Imperial forces. Respond in the Emperor's name." She activated her vox unit and sent out a general broadcast. She hoped she was not alone in this strange world.

"Burn, heretic." Xander shouted as he leveled his incinerator at a group of monsters and strangely dressed humans charging at him. Screams of pain and death echoed across the street as the burning promethium did its grisly work.

"Come and taste the Emperor's wrath." He leveled his nemesis force spear at the survivors. His silver-grey power armor gleamed under the fire from the burning corpses. The monsters decided that fighting the armored behemoth was not the best idea, and they scrambled away.

"This is Grey Knights Terminator Siler Radan. I am at your service, honored Inquisitor." Xander replied, before focusing his psyker powers to locate the Inquisitor.

"The Omnissiah guides my hand." Willow used her lasgun to push back several creatures that assaulted her. A large furry creature managed to push through, but was stopped as a long robotic arm with a large claw grabbed its arm and snapped it.

Using this distraction, Willow fired several shots in its skull. "Enginseer Vana Osus responding. How can the Machine Cult serve the Inquisition?" She retracted her mechadendrite and activated her auspex to locate all Imperial markers.

Buffy released a sigh of relief. A single Terminator and an Enginseer was not a large force, but it was enough to figure out what was going on. Ever since she suddenly appeared in this world, she had a strange feeling about the place. There was also the feeling she got from the Immaterium as she drew power from the Warp.

The most painful revelation was the complete absence of the Astronomican and the Emperor's light. This fact alone nearly brought her to despair as it brought thoughts too terrible to contemplate. However, she was surprised to feel that she could not sense even a trace of the Ruinous Powers as well.

"Inquisitor, may I ask what is going on? I have scanned the sky, and all constellations point to a single fact. This is Holy Terra." Xander walked through the street unmolested while Buffy was busy fighting a pair of vampires.

"I do not know, but I sense some sort of foul sorcery blanket this city. Perhaps if we find the source, we may be able to find what is going on here." Buffy replied.

"It is indeed a most strange place the Emperor has led us. I wonder how it is we ended up here?" Willow managed to reach the pair of psykers as well.

"I believe we will find our answers this way." Buffy pointed in a direction, and the trio started walking.

Meanwhile, the local vampire leader Spike decided to look what was going on in the city as his girlfriend Drusilla made a somewhat confusing prediction.

The city was in complete chaos, and all sort of creatures were running about, doing all sorts of mayhem.

"Now this is fun." He grinned, his vampiric face lit in glee at the havoc around him.

"Cleanse. Purge. Kill." He heard a strange voice shout, followed by the sound of gunfire and explosions accompanied with flashes of flame.

"Oh bloody hell." He stopped in his tracks as he saw the three figures that were blasting through the crowd of creatures in the streets. For the most part, they killed only a few, their attacks serving more to clear them a path.

Of the three, he only recognized one, but that was enough to send a shiver of pure terror down his spine as he watched the Slayer simply wave her hand and a dozen creatures simply fly everywhere as some invisible force flung them.

'Maybe I should look into the quickest way out of town, just in case.' Spike's face became human again as he turned around and retreated to his hideout.

"This is the source of the spell affecting the city." They walked into Ethan's and found a large altar with a two-faced bust on it.

"Then our course is clear." Xander hefted his spear and swung it down, obliterating the statue and breaking Ethan's spell. Of the sorcerer, there was no trace.

"What the…" Buffy shook her head as she felt the spell's effects fade from her body.

"Xander, what happened to you?" Willow shouted as she caught sight of Xander. He was currently seven feet tall and built of solid muscle. He was also covered in a drape as his costume lay in pieces around his feet.

"I have no idea, but I think it's a good idea to get out of here." Xander replied. Regardless of what the hell had happened, he had no desire to let the two girls see him naked.

"I see. This is a truly fascinating event. You say none of the other people affected retained such changes?" Rupert Giles, the high school librarian and Buffy's Watcher was quite shocked when the trio walked in the library.

"Yes. As far as I saw, we're the only ones that retained more than mere fragments of the people we turned into." Buffy replied.

"What exactly did change in you?" Giles swore to hunt down and murder his old friend very, very slowly, but first, he wanted to find out what had happened to the three children under his charge.

"I'll go first, if you don't mind. I was dressed as a Mechanicus Enginseer. While my body didn't change, I do have the knowledge on how to construct almost any technology used by the Imperium. Putting that knowledge to practical use will be very difficult, though. A lot of the technology is very advanced." Willow replied.

"I was dressed as an Inquisitor of the Ordo Malleus. While I didn't change as much as Xander, I did get a new ability out of this. I am now a psyker. Before you ask, a psyker is a human with the ability to draw power from the Immaterium and use it to perform various acts in the real world. Normally, this is a very dangerous practice, as the Warp is inhabited with a wide host of malignant creatures. Here, however the Warp is quite calm. I sense no entities in it, malignant or otherwise." Buffy sighed before continuing.

"The knowledge and the memories are the worst, though. I remember wars, death and sites of daemon worship that would drive a person mad. To think that such evil can exist in the universe breaks my heart."

"Not all of these memories can be that bad. Surely you some good as well." Giles tried to comfort her.

"Yes, there was. I also remember acts of courage, valor and dedication that served as an inspiration to all who have witnessed them. I have seen the worst, as well as the best in humanity." She grinned sadly. Giles could see that the trio would recover from the ordeal, but it would be a slow and very difficult path.

"As far as memories and powers go, I got pretty much the same deal as Buffy, and let me tell you, some of the daemons this guy fought were real nasty. As for changes, where do I start?" Xander sighed.

"I was a Grey Knight Terminator, an elite genetically altered soldier. There are a number of special implants throughout my body that are meant to enhance or aid me in some way. Why they're still here, I have no idea. All I know is, if even one of them gets messed up, the rest will follow and then it's all over for Xander Harris." Xander grumbled.

"How likely is that from happening?" Giles asked.

"The chance is small, but not something to ignore. All Space Marines go through regular check-ups to ensure that their implants are functioning well as well. There's also the fact that I have no working armor or weapons. I feel kinda naked without them. Can you make something, Willow?"

"You want me to make a functioning Terminator armor and its associated equipment using the technology available in this day and age?" Willow gave him an incredulous stare. "If I manage to stumble on a working STC machine somewhere around here, then sure. Otherwise, it will be extremely difficult."

"How difficult? I would prefer to have some weapons as well. Not all daemons are as easily killed as vampires." Buffy grinned. She had also gained a lot of combat training with the memories, and she was eager to get her hands on the force sword again.

"The ability to manufacture the raw components alone like adamantium, ceramite and other such materials will take a lot of time, effort and money to obtain. And that is just for the most basic stuff. I don't even know if it will be possible to create the more complicated stuff." Willow complained.

"Wills, if anyone can do it, it's you. Meanwhile, we'll have to make do with that is already available in the world." Xander gave her an assuring grin. While all three teens have been changed from the experience, Xander's change was the most profound.

Willow was already a geek, and her evolution into an Enginseer was not a major change to her personality. She had become more focused and analytical, but nothing too drastic.

Buffy's experiences had already tempered her heart against evil, and her new memories as a member of the Ordo Malleus only enhanced her dedication to defend humanity against evil.

The memories Xander inherited turned him into a warrior and through the experiences and events they carried, into a leader. He had memories of leading squads of Grey Knights into battle, men who put their faith in him to make the best plan to lead them to victory. It was a profound experience that could make or break a person.

Xander proved he had a spirit worthy of the Grey Knights as he refused to buckle against the horrors that suddenly engulfed his mind, but fought them and emerged victorious, just as he knew the girls had done. Their eyes showed the determination and the spark of victory.

Left unsaid was the fact that while possessed, they killed several possessed people and children. The latter hit the trio especially hard, and they all knew that this was a burden they would carry for the rest of their lives, but at the same time, they swore to fight even harder against all evil.

"The most important question now is, how do we explain Xander's new appearance?" Giles broke their contemplation.

"We can just say he was injured tonight. Something that will keep him away from school for several months. We can say we'll tutor him to keep him on track, and when he comes back, he can just say he was working out a lot. It's a bit of a stretch, but stranger things have happened in this city." Buffy proposed an idea after a few minutes.

"It will have to do. I hope you'll be able to make the whole ruse pass scrutiny?" Giles turned to Willow who gave him an assured nod.

"Then I suggest you should get back home. It has been a long night." Giles ushered the teens out of the library.

'Now, Ethan old mate, where are you?' Giles's face took on a grim smile. No one messed with his charges on his watch.