Real Name: Raven Darkholme
Mutant Power: Ability to morph into other objects, animals, or people
Voice Actor: Colleen Wheeler (as Mystique and Principal Darkholme); Nicole Oliver (as Risty Wilde)
First Appearance: "Strategy X"
Back Story: Mystique, during some point in her life, got involved with Magneto, and joined his ranks sometime in the past (exactly when is unclear). Soon after, she gave birth to her son, Kurt Wagner, aka Nightcrawler, and although he probably had some apparent Mutant attributes from the get-go, such as blue skin, Magneto performed some experiments on the then-infant which made him all the more freakier. Mystique was horrified that Magneto had done this to her son, but still remained loyal to Magneto for several years afterwards. Mystique also adopted Rogue when the girl was 4, buy why Rogue doesn't remember this wasn't revealed. After certain events in "The Cauldron", in which Magneto effectively refused Mystique admittance to the "sanctuary" of Asteroid M after she lost a trial fight to Storm, Raven officially renounced her allegiance to Magneto, along with the rest of the Brotherhood. She became genetically enhanced by the machine in Asteroid M shortly after she broke into it along with some other members of the X-Men and the Brotherhood. An oddity of this is that her appearance directly after she came out of the machine is very different from the her appearance the first time we see her in Season 2 (essentially the same as Season 1, but with yellow, instead of blue, eyes). I suppose the explosion of the genetic enhancer could have devolved her partially, but not completely. Either that, or chalk it up as a plot hole, I dunno. Anyway, after "The Cauldron" Mystique abandoned her identity as the Principal of Bayville High School so she could have more time to work for herself and her cause. She also made herself a new uniform, probably to renounce her former affiliation with Magneto. She soon adopted the new identity of Risty Wilde, supposedly an average teenager at Bayville High who befriended Rogue. She used this identity to secretly extract some information from Cerebro on the X-Men and Xavier's history, and to be with her adopted daughter. In the last half of the series, she led the teenage Brotherhood members, but not nearly as directly as she did in Season 1- she tended to disappear rather often. She was finally found out by Rogue in "Self Possessed", and has since completely lost the Risty persona. Mystique turned into stone at the end of Season 3, and was supposedly killed by Rogue, but she was somehow shown to be alive near the end of the series, as one of Apocalypse's four horsemen. How and why this happened was not revealed, unfortunately- I can only assume that it was going to be explained, had there been a Season 5. She eventually was released from Apocalypse's control after he was vanquished, and she's supposedly up to her old tricks again.
Personality: Mystique is a very bitter person, probably due to past events in her life such as effectively losing her son Kurt to the X-Men. Although technically the strict, no-nonsense leader of the Brotherhood of Bayville, she's left three times for long periods of time without informing the Brotherhood of her whereabouts, leaving them mostly to govern themselves. Her top priority in life, though, is defeating Xavier and his X-Men, as well as Magneto and his recruits. Her second priority is to wage war with the human race, just like Magneto, but this has become sort of put off to the side since the beginning of Season 2 in favor of the other two objectives. She's definitely a very vengeful sort- watch out if you ever cross her, as is shown numerous times, such as in "Turn of the Rogue", "The Cauldron", and "Blind Alley". Besides Xavier and Magneto, she also has a special hatred for Cyclops, who imprisoned her in Area 51 for a while, and Quicksilver, who betrayed her and the rest of the Brotherhood to Magneto. She also has a bit of a semi-loving tie to Kurt and Rogue, both technically her children. She's a little reluctant to hurt them, but not as much as you'd think she'd be...
Final Reflections: Mystique had a very evil, yet well fleshed-out personality, and she surprised you with her appearances more than once in the series. However, some of the stuff that happened to her just wasn't explained very well, and that's my main problem with her. Like I've mentioned earlier, why did her appearance change between Season 1 and 2? And how did Apocalypse gain control of her when it was very obvious her stone remains were destroyed in "Impact"? One can only speculate.