Vampires were outed to the world after Harmony bit A. Dick.
Giles was brought back to life by his weird aunts who recreated his body as a teenager, with all the hormones that go with it.
I have to admit, even though this all sound a bit bizarre, I'm still curious to check out the comics, just to see exactly how everything plays out.
God, I forgot Andy Dick and TMZ played a role in outing vampires to the world.
To be fair about that last point, it was one of the few bizzare choices that worked like gangbusters.
Whedon and his "writers room" knew they were going to bring back Giles in Angel & Faith, but he gave Christos Gage 100% creative control over how it was done while giving him three options. Gage felt that if Giles came back like nothing happened, it would have cheapened his entire 25 issue Angel & Faith arc about consequences. If he brought him back as "Ripper" he would have been too much of a wild card (and he was afraid that future Buffy comic writers would have Ripper lust over Buffy).
By bringing him back as a twelve-to-thirteenish kid (which was a mistake on his aunts' parts and definitely not the plan), it had genuine consequences for Giles. He was reset to himself at that age in terms of everything except his memory. He still had all the magical knowledge, but had to relearn how to use magic. He now had hormones controlling his emotions. Plus is gave Gage a great Buffy/Giles dynamic to work with when he took over Buffy in Season 10. The surrogate daughter was now the surrogate mother.
By bringing him back as a twelve-to-thirteenish kid (which was a mistake on his aunts' parts and definitely not the plan), it had genuine consequences for Giles. He was reset to himself at that age in terms of everything except his memory. He still had all the magical knowledge, but had to relearn how to use magic. He now had hormones controlling his emotions. Plus is gave Gage a great Buffy/Giles dynamic to work with when he took over Buffy in Season 10. The surrogate daughter was now the surrogate mother.