yes and yes.
forget what happened, but he was definitely a baddy - though I thought a girl took him on so I'd have guessed buffy.
the black woman was the evil god-come-back-to-earth that tricked people into loving her and angel's kid could see her real self but followed her anyway cuz she gave him purpose. but bringing that up alsore reminds us that angel had a son, and that got more than a little ridiculous - although I suppose cordelia's child was a worse plot move.
edit: yep, it was btvs:
# "Buffy the Vampire Slayer" playing "Caleb" in episode: "Chosen" (episode # 7.22) 20 May 2003
# "Buffy the Vampire Slayer" playing "Caleb" in episode: "End of Days" (episode # 7.21) 13 May 2003
# "Buffy the Vampire Slayer" playing "Caleb" in episode: "Touched" (episode # 7.20) 6 May 2003
# "Buffy the Vampire Slayer" playing "Caleb" in episode: "Empty Places" (episode # 7.19) 29 April 2003
# "Buffy the Vampire Slayer" playing "Caleb" in episode: "Dirty Girls" (episode # 7.18) 15 April 2003
edit2: it was season 7, which I'd just as soon forget. hence the not knowing. oh gawd. I even speak like whedon. no wonder I like his pen.
edit3: ok. getting tired of tracking my changes here.... just notices you said "in buffy" in the first place. oye!
edit4: now I'm kinda bored. but you're exactly right. he was the "invincible" guy who was kicking buffy's ass (vague that up a bit, eh?) and angel showed up to give her an amulet or some shit. think it was in a cemetary masaleum. lame crossover.
Life ducks, and you sigh.