Rupert Giles is a character from the Buffy the Vampire Slayer television series played by actor Anthony Stewart Head. He is a British Watcher given the responsibility of teaching and training Buffy Summers in her role as Slayer. In his early years with Buffy he also worked as the librarian at Sunnydale High School. However, with the destruction of the school, he took over a magic shop, The Magic Box, in the town. Over time, and with Buffy becoming older and wiser, he found his services as a Watcher required less and less, and eventually decided to return to his native England, moving to a place near Bath.

Being a Watcher for Giles is continuing a family profession; his father was a Watcher as well as his grandmother. It was believed that being a Watcher is a calling as much as being a Slayer is.

Young Giles didn't like the idea of a calling and he left university for a while to rebel. He met up with a crowd that included Ethan Rayne, Philip Henry, Diedre Page, and started his involvement with black magics, and demon summoning. He was known by the nickname "Ripper".

Giles went back to answer his calling as a Watcher out of guilt and/or a sense of awakening, when one of their friends was killed as a result of summoning Eyghon, a demon that possesses the dead or the unconscious. Ripper's group summoned the demon, because the Eyghon demon gives the host it possesses a sense of ecstasy.

When Eyghon returned decades later, all of Ripper's former group who got the tattoo/mark of Eyghon were killed, with the exception of Giles and Ethan Rayne.

There has been talk about a spinoff series from Buffy the Vampire Slayer for the BBC called Ripper, though it is thought (in mid-2004) that this is no longer likely to happen.