Here are seven key characters (but by no means all of the regulars) from the series:
- Olivia Dunham - The lead character played by Anna Torv initially very similar to Sydney Bristow from Alias (as Kate would have been on Lost if Jack had been killed off in the pilot as initially planned!), Olivia emerges as the contemplative and soulful heart of the series, whose ties to the dark matters that haunt its past and present are continually explored across two realities.
- Walter Bishop - The troubled genius rescued from an insane asylum in the pilot, portrayed brilliantly by John Noble, Walter's life defines the whole course of the series in ways that take time to understand, though it's his early life's work that gets himself and everyone else in trouble, and his reconciliation with these horrors that gives the series its emotional depth. But yes, he's also the nutcase bursting with hilarious non sequiturs. It would just be a shame to only think of him in that way.
- Peter Bishop - The constant bridge between Olivia and Walter in ways that become more and more important as the series develops, Walter's son as portrayed by Joshua Jackson is the guy you hate to have around but absolutely need, and he becomes quite essential.
- William Bell - Walter's early-career partner in science appears occasionally, and you will relish each visit because he's played by Leonard Nimoy. The climax of the fourth season closes the book on half the series as William thinks he's finally perfected Walter's fondest desires.
- Nina Sharp - You never quite know if Nina, COO of Massive Dynamic (Apple if Steve Jobs had been a quasi-evil genius), is in fact an ally of Olivia's, and Blair Brown plays this ambiguity to perfection. Plus Nina has a robotic arm. She hides it most of the time, but it's still one of the coolest elements of the series.
- Sam Weiss - Sam appears as an independent consultant to Olivia in the second season, and he's yet another voice of the strange who offers reassurance when it seems impossible. His importance is elevated in the third season even though he ultimately makes very few appearances, but his impact remains significant. Played by Kevin Corrigan, who somehow still hasn't been earmarked by anyone for a lead role in something (at the very least, plug him into a franchise like CSI or something!).
- September - One of the most distinctive characters in the series is the bald Observer who turns out to have quite a bit of sympathy for our protagonists, even though the rest of his kind most certainly do not (the whole fifth and final season is all about that). Michael Cerveris played this role so well, it hardly mattered his appearances were always kept to a minimum.
- David Robert Jones - Not to be confused with David Bowie's given name (apparently), the wicked genius played by Jared Harris is the evil counterpart to all the good guys in the series.