Assassin's Creed III. But it's done in the same game. Well, kinda.

Only it sorta backfired as most people I know prefer Haytham to Connor.

Search for concepts like "false protagonist" and "rogue protagonist". See below pages at Giant Bomb:

<span class="bold">False Protagonist</span>
You may think you know who you are playing as, but do you?

<span class="bold">Rogue Protagonist</span>
The original protagonist of a game becomes an antagonist in the sequel.

Yea, was going to mention that. In D1, the Warrior is one of Leoric's two sons, that absorbs the soul of Diablo and in D2 he is the Wanderer that you see in the cinematics. D1 again, the Rogue class in a fallen / corrupted ranger you fight in D2.

In Warcraft 3 you play as Arthas in two campaigns, basically becoming the Lich King. In WoW: WotLK, you go and kill the Lich King.

You also play as Illidan during two campaigns, who you fight as Arthas at the end of Warcraft 3.

Across all Starcraft games, you switch between protagonists and villains all the time.

One of my favorite switches of all time is an ANTAGONIST becoming a PROTAGONIST in the movie Rocky Horror Picture Show - you go from hating and fearing Frank-N-Furter to pitying and caring/loving him. Every time I watch it, it is pulled off, so wonderful.

I like it, sounds very posh!

Nintendo did it again in the Mario Land series, Wario was first introduced as the antagonist of ML 2 but in ML 3 he was used as the main character.

I only saw 1 and 2. Did they keep recycling that "curve"/surprise/twist?

The survivor from 2 is the baddie in 3 and so on and so on and so on. Got pretty predictable. :P

There are a few examples of the protaganist appearing in the back story to the sequel as having become the bad guy. KOTOR 1 & 2 spring to mind, where the character you played in 1, has gone on to be a sith (I assume that was unrelated to what you actually did in 1).

I liked how it worked in Kohan 2 where one of the bad guys is grudgingly working with the good guys (though such enemy of my enemy stuff is common). The difference being that you slowly discover that Melchior actually does want redemption to some extent.

After the first saw the plots barely made sense. It just became complicated torture porn.

That was the one thing I didn't like about Prototype. After playing through the entire first game as the goodest good guy I could be, I pick up the second and not only am I playing as someone else (which was not bad in itself), but my former good guy pseudo superhero is an evil clone bastard now. If I had played the first game evil, it might have been better, but as it is, the tone change between the games was quite jarring.

They could say that a bunch of gog derepper's was to blame.

Not a fan. I took JC's ending because I couldn't bring myself to shoot him, despite not agreeing with him.

I hated it with prototype. Apparently people didn't like that Mercer was kind of a psychotic dick on the first one, so they made him the villain on the second one and casted a patriotic soldier trying to save his daughter as the main character. Who behaves just as badly, but it feels 10 times more wrong as he's supposed to be a good guy and you're supposed to like him. I'd rather have the outright psycho than a hypocritical asshole.

LOL

Imagine someone gets down reped to -5 and becomes a super villain like the Joker who wants to see the world burn.

I'm working on that idea.