Hot on the heels of a brand new trailer for X-Men: First Class comes more information about the main mutants that will be appearing in the prequel – including some intriguing nuggets of information about Sebastian Shaw (Kevin Bacon), a villainous character who hasn’t been featured all that heavily in the film’s trailers up to now.

Fair warning: We’re about to enter MILD SPOILER territory with these character details, so if you want to head into the next X-Men movie knowing as little as possible in advance, you might want to skip ahead and just check out the new poster for the film (at the end of this article) instead.

Still here? MSN has posted a character guide for ten important players in X-Men: First Class. Each character description was given by the respective actor/actress who played them – so bear that in mind while you read on.

To start off, here’s a bit from James McAvoy discussing the young Charles Xavier:

“Charles has this connection to everybody because he can feel their experiences and see them. Their memories are his memories. But he wasn’t looking for Erik. He didn’t know Erik was there and he suddenly felt him. And perhaps he’s never connected to Erik in quite the same way he’s connected to other people. I think there’s a little bit of vying for who’s in charge, and there is a feeling between them from Magneto that, ‘you’ve got the brains, but I’m your trump card, pal,’ at every venture. ‘I’m the most dangerous dude in here, and you know that and I know that,’ and I think by the end of the film we come to an understanding about that as well.

We do have completely different views as well, and what’s quite nice is that those scenes don’t come to a nice reconciliation at the end. They’re left, so the tension carries on through the movie.”

There’s nothing exactly shocking about McAvoy’s description of the young Professor X, but it’s a comforting read all the same. Everyone already knows the union between Xavier and Erik Lehnsherr (Michael Fassbender) ultimately disintegrates, but the complex dynamic between the two men – with their different mindsets and clashing ideologies – looks (to me) to be intelligently explored and examined in an interesting way in X-Men: First Class.

Fassbender, however, is the one with the goods, revealing some juicy details about the plot of First Class, and how Sebastian Shaw fits into the equation – amidst all the political intrigue and coming-of-age drama in the film, that is:

“At the start of the movie we get introduced to Erik as a boy. We start in the concentration camps with him and it cuts to 20 years later and it’s the early 60s and it’s Erik as a grown man. He’s on a quest to get Sebastian Shaw, played by Kevin Bacon. Shaw had him in these concentration camps – and as we know the Nazis were doing lots of experimentation with all sorts of things like measuring skull size and brain size and running experiments on human beings, essentially. Shaw is trying to unleash this power in Magneto – he’s recognised that he can manipulate metal – and so we catch up with Erik on a quest to basically hunt Shaw down.”

There a whole lot more in the way of cool revelations about the characters in X-Men: First Class – including word about the pivotal role Mystique (Jennifer Lawrence) plays in Henry “Hank” McCoy’s (Nicholas Hoult) transformation into Beast, how Alex Summers/Havok (Lucas Till) controls his powers (hint: watch the newest First Class trailer and you’ll see), and ultimately what side of the war between the X-Men and the Hellfire Club Angel Salvadore (Zoe Kravitz) ends up on. So head on over to MSN to check those out.

Lastly, yet another poster for X-Men: First Class has been released, and while it’s not as lackluster as some of the previous one-sheets, this new poster still looks kind of sloppy. Not to harp on it too much, but I have to say: to me, Magneto’s helmet appears almost shoehorned in between the top of the “X” and the whole thing still looks like a less-than-stellar photoshop job. It’s a good thing the trailers for the film have been top-notch – the rest of the marketing campaign hasn’t exactly inspired much in the way of confidence.

See what I mean by checking out the new X-Men: First Class poster (via Yahoo! Movies) below:

X-Men: First Class hits theaters this summer on June 3rd.