C is for...

Alfred CAHILL
What happens when you miraculously recover after being stabbed? You believe you've been resurrected for a holy war, that's what, and no-one - least of all some Scottish lunk - is going to tell you otherwise (A20, 'Avenging Angel'). Facial similarities with the bass player in 80s pop combo Spandau Ballet are, of course, entirely coincidental.

CASSANDRA
Otherwise known as the Witch of Donan Woods, Cassandra first met Duncan when he was a 13 year-old boy (and pre-Immortal). They met again in 1995 to fulfill a prophecy and later indulge in some rumpy pumpy (E1, 'Prophecy'). Later we learned that she was born during the Bronze Age, and was kept as a prisoner at the Four Horsemen's Camp for a short time. Perhaps unsurprisingly, she's not their biggest fan (E11, 'Comes a Horseman'; E12, 'Revelations 6:8'). Actress Tracy Scoggins replaced Claudia Christian in Babylon 5. Claudia returned the favour with a sixth-season appearance on Highlander (F10, 'Two of Hearts').

Regan COLE
An immortal-cum-bounty hunter, and one of five female immortals given an entire sixth-season episode to themselves (F9, 'Deadly Exposure'). She first met Duncan in 19th Century England - in bed, of course.

D is for...

DARIUS
An Immortal who had a touchy-feely Quickening after centuries as a warmonger and became a monk. Duncan first encountered him at Waterloo in 1815. (A13, Band of Brothers).

DARK QUICKENING
Duncan had one of these when he took the Immortal Coltec's head, with predictably tragic consequences. It seems all the evil the holy man (or Hayoka) had absorbed over the centuries was channelled into the Highlander. Silly boy. (D13, Something Wicked; D14, Deliverance)

Joe DAWSON
Duncan's personal Watcher and high-ranking member of The Watchers (see W).

Charlie DE SALVO
A mortal friend of MacLeod's who originally owned the Dojo in Seacouver that MacLeod moved to after Tessa's death. He, along with Joe Dawson, also neatly fulfilled any American series' requirement of featuring an ex-army veteran as one of its regulars. His last appearance in the show resulted in a tragic exit (D2, 'Brothers in Arms').