please note, this a total re-write form almost scratch, not just a clean up job on my first version of this

Immortals, men and women who live for hundreds, even thousands of years. They have lived among us since the birth of mankind, hiding in the shadows. Some of them cut a path of destruction through the centuries to satisfy their own selfish greed, seeing mortals as mere play things, but others act as heroes and use their gift to protect mankind. There is one thing that binds all immortals, both good and evil, there is a creed that holds for all of them:

There can be only one.

When one immortal challenges another, they fight to the death. The winner takes the losers head, and their strength and knowledge with it. There is one rule immortals must follow, inside or outside of these duels, they cannot kill on holy ground.

One of these heroes is Duncan MacLeod, a warrior born over 400 years ago in the Scottish Highlands. For centuries he has stood a silent protector, facing evil immortals and protecting the human race. He has fought with freedom fighters to over-throw dictators, and led oppressed peoples to freedom. He even fought in the American Civil War, and helped lead freed slaves to safety.

Now, an evil from another world sets her sights on him.

After the mess with "Gabby Gums" Applebloom still has to apologize to one last pony. She learns that no matter what, some ponies are always there for you.

Edit: I cleaned up the grammer as best as I could myself.

Edit: Mucked up the first time, now the edited version is up.

Immortals, men and women from all over the world who live hundreds, even thousands of years. Throughout the centuries they have walked among mortals in secret, moving and taking new identities as needed to stay hidden. Some abuse their power, treating normal humans as their playthings and carving a path of destruction to satisfy their selfish greed. Others use their gift to act as heroes, and protect humanity from evil.

But one thing holds true for all immortals. They fight a secret war amongst themselves, each with the goal of being the last. When a challenge is called forth two immortals meet blades and fight to the death. The victor takes his foes head and with it their power. There is only one rule in these battles, an immortal cannot kill on holy ground.

One of them is Duncan Macleod, a warrior born in 1592 in the Scottish Highlands. He has spent 400 years fighting evil immortals and protecting us in secret. Tonight with the drop of a head a great evil sets her sites on him, and lures him into her world.

Edit: Completely overhauled with the help of the people in the TvTropes Pony fic thread.

Edit: This version is dead, check my profile for the new version of the story where it will continue.