The idea for taking the story in this direction came from the following story from fanfiction.net:http://www.fanfiction.net/s/2595520/1/ It also played a large role it my approach to the whole horseman thing. The title was Eternal Champions I would recommend reading it.
Important note: This is AU in the stargate universe after the replicators and Anubis have been defeated for good. The reason for this... I moved and no longer have cable so the later seasons are lost to me.
As usual I own nothing, not Buffy, not Stargate, not Highlander. Even my shoes have six payments left on them.
Summary of the Horsemen series(I would still recommend reading the other parts, things will make more sense):
Willow and Xander get wished into the Highlander verse where they are immortal and the date is 3000 something BC. After many many years there personalities become so warped and jaded that they eventually meet up with Silas and Methos and become two of the four Horsemen of the apocalypse. Unfortunately when they finally get back to Sunnydale none of the gang can accept what they have become and undo the wish.
Xander and Willow die, reactivating their immortality and memories(reasons given in actual story). After outliving the other Scoobies, with the exception of Dawn, they open a portal to the Highlander verse using Dawns blood after feeling the irresistible Call of the Gathering. There they meet up with Silas and Methos and kill off the other immortals. However the Call proves to strong and to keep the four from killing each other off Willow sends them to their own little universes. Special note, in Willows world, magic is far more limited then in Buffy world.
Willow The Ancient
A Time Will Come That We Shall Return
War Will Press In From The Serpents
Pestilence Will Be Released In A Mechanical Plague
Famine Will Sow Discourse Among The Furling
And Death Will Arise From The Ascended Snake.
In The Time Of The Four Races' Extinction The Four Will Wake
We Will Stop The Plagues, The War, The Great Death
But We Shall Exact Our Vengeance And The Ascended Will Fall.
I Brought Light To This World
And By The Bringer Of Light I Will Return
(Graffiti found on the walls of Atlantis)
Samantha Carter was going over the ship's diagnostics once again. This was going to be the first time the Prometheus had attempted to travel beyond the Milky Way galaxy and Carter was a little worried about whether the ship could handle the ride. There were just too many things that could go wrong when dealing with the dozens of different alien technologies the U.S. government had mashed together to make the thing fly. Most of which was barely understood.
As a trial run, they were expected to rendezvous with one of Thor's ships in the Asgard home galaxy. All of SG1 was expected to be on board as a sort of political statement. It seemed that their previous accomplishments had garnered enough attention that the leaders of both the US and the Asgard liked to use them for the occasional photo-opp. A secondary purpose of the mission was as a final send off for Jack before he retired. At nearly seventy years of age, he was looking forward to the quiet life. Sam caught a glimpse of herself in one of the stainless steel panels and sighed. She was no spring chicken herself anymore. Not that she was vain, she just worried about the day she would start looking as old as her father, who had more or less stopped aging after becoming a host to the Tok'ra Selmak. Chasing away thoughts of her own mortality, she turned back to the control panel of the engine room.
She was so used to the systems of the Prometheus that she barely had to pay attention as she ran the routine diagnostics on the systems. Eventually she was satisfied with the Naquadah intake of the main drive and radioed the captain to give the all clear for jumping to hyperspace. Without further ado, the captain gave the order to leave the Milky-way.
As soon as the drive engaged Carter knew something was wrong. The engine was pulling about four hundred times more power from the generator than should have been possible. Without hesitating Carter slammed her hand down on the comm and shouted, "I'm causing a manual shutdown of the drive. At the rate it's burning the reactor will go critical in under thirty seconds!"
The captain radioed back, "Acknowledged. All hands brace yourselves."
Sam had already begun typing in the codes required to shut down the drive and separate the critical mass of the Naquadah core. As the final code was entered the ship was ejected from hyperspace and into intergalactic space. The massive jarring caused by the transition threw Sam across the engine room into one of the techs who had been watching the whole thing in a state of shock.
Gradually Sam regained consciousness. She found herself in the ships infirmary looking up at the faces Jack, Daniel, captain Grahams, and her doctor Cassandra Frasier. Jack spoke without his usual humor, "Sorry to cut your bed rest short, but we need everyone's help to get the ship to the nearest system."
Sam shook off the strange dream she had been having about swords and horses and turned to the captain, "What's the situation?"
The captain looked grim and said, "We're stranded somewhere between the Asgard's galaxy and our own, and our engines are all but scrap."
Sam instantly understood just how bad their situation was, without the hyperdrive it would take millennia to get back to Milkyway. Siting up she asked, "What did Jack mean when he said that we had to make it to the nearest system?"
Daniel spoke up, "The ship's sensors detected a solar system less than ten light-years away, we're hoping we can touch down on one of the planets and make our repairs... That is if we can even make it that far." He nervously ran his hand through his hair, displacing the carefully crafted come-over.
Sam's brow furrowed in confusion, "That doesn't make any sense, finding a solar system out here, within ten light-years, is less likely than finding an ant floating on walnut at the center of the pacific."
Jack cracked a smile and said, "Well looks like we're in luck then."
Sam returned his infectious grin with a weak smile of her own, "I'll get started then, I still don't know how the drive could have acted up like that."
Jack slapped her on the back and, with a slightly forced cheer, said, "Well I'm sure you'll be boring us with theories soon enough." Sam shook her head and got to her feet, ready to do what she could to fix the current mess they were in.
Normally I don't like reading multiple crossings since they become too confusing, but here I am writing one. I entreat you the readers to yell at me if things get disorganised or confusing. Hope you enjoy.