"Into the Dark Age," by Sadbhyl
For the life of me, I can't remember how I stumbled across this fic. I'm a lover of dark Giles on occasion. Also, I love Ethan, whom I think was not used to his potential on the series, and then was greatly upset when I saw what happened to him in the comics.
Into the Dark Age by
sadbhyl. Buffy makes a wish by mistake and is taken back in time to when Giles was Ripper and still hanging around Ethan. It's dark and erotic, but there's still a good story behind it. It's quite long, though, so get comfortable. You won't be able to turn away once you start.
http://www.sadbhyl.com/Stories/Dark%20Age/darkage01.htm
Into the Dark Age by
sadbhyl. Buffy makes a wish by mistake and is taken back in time to when Giles was Ripper and still hanging around Ethan. It's dark and erotic, but there's still a good story behind it. It's quite long, though, so get comfortable. You won't be able to turn away once you start.
http://www.sadbhyl.com/Stories/Dark%20Age/darkage01.htm