Based on the comics from Excalibur Vol 3 14, X-Men Unlimited Vol 1 36, the Days of Future Past storyline, the Astonishing X-Men storyline, "Torn" and X-Men issues 129-131.
- James Howlett Logan/Wolverine (Steve Blum) - had been in the war with Charles and Carmen long time ago, he is practically Kitty's "uncle"
- Scott Summers/Cyclops (Rino Romano)
- Emma Frost (Juliet Landau) - had been watching Kitty ever since she was a baby, making Kitty think that she is her "Fairy Godmother", as she was tasked by Carmen offscreen to watch over Kitty
- Kitty Pryde/Shadowcat (Hynden Walch) - became part of the X-Men ever since she was 13 years old, as she first confronted the mysterious Hellfire Club, she was devastated when her father, Carmen was killed offscreen
- Lockheed - Kitty's best "dragon" friend
- Hank McCoy/Beast (Diedrich Bader)
- Piotr Rasputin/Colossus (Alan Tudyk)
- Brotherhood of Mutants:
- Raven Darkholme/Mystique (Gina Gershon) - plans to assassinate Senator Kelly, which would lead to the Dyostapien Future of Sentinels taking control of Earth
- John Allerdyce/Pyro (Danny Cooksey)
- Fred Dukes/Blob (Bill Faggerbakke)
- Dominikos Petrakis/Avalanche (John DiMaggio)
- Irene Adler/Destiny (Candi Milo) - Rogue's "fairy godmother"
- Anne Marie/Rogue (Ashley Johnson) - Mystique's foster daughter, she starts to befriend Kitty
- Senator Robert Kelly (Gary Cole) - his death may lead to the Sentinels starting to control mankind
- Carmen Pryde (Jim Meskimen for adult, Cameron Bowen for Junior Soldier Carmen Pryde) - Kitty's father, was once best friends with Professor X and Logan in the military, Carmen asked for Charles to be his best man at his and Terri's wedding, once they're done with Lucifer's Rampage, Charles had objected for Carmen to stay put as Charles will deal with the terrorists, but when Carmen refused to leave Charles' back, he accidentally got Charles legs broken, Logan followed behind and saved Carmen from dying, 16 years later, Carmen was now a father to Kitty and husband to Terri, when Mystique attacked a lab in Shaw Industries, Carmen made a quick recording to Kitty, messaging her to make him proud, before the camera goes offscreen, he wasn't seen later until near the end where he reveals himself to Logan, having spent 17 years hiding his robotic self, he feared that the blast from Lucifer that got him hit when Logan was protecting him was infecting his nervous system, so with the power of Sentinel tech, he would control the Sentinels by himself by his technopathy, which means he can control technology.
- Terri Pryde (Tress McNellie) - Kitty's mother, who was shocked at Carmen's death, unbestknown to her is that Carmen's alive.
- Bolivar Trask (Neil McDonough) - Logan and Carmen's old friend in the military, he is a scientist, when Carmen was in Major rank, he helps put Carmen into shape by Sentinel Tech, 16 years later, he is working under Senator Kelly's order to hunt down Logan and the X-Men with his Sentinels, though his son, Larry had a vision that the Sentinel Apocalypse will start with Senator Kelly's death, and the Sentinels will take control of mankind, which makes Bolivar turn in his Sentinels to Shaw Industries
- Hellfire Club:
- Sebastian Shaw/Black King (Michael Gross) - the main antagonist, CEO and Chairman of Shaw Industries and orcastrater of the switched arrangement of the Sentinel Apocalypse, and that they need Magneto as the puzzle piece to reprogram the Sentinels, for "Project: Wideawake"
- Larry Trask (Freddie Rodreguez) - Bolivar's son, who visioned the assassination of Senator Kelly, which caused Bolivar to hand the Sentinels over to Shaw Industries, unknown to Trask, Shaw needed Magneto's help to reprogram them
- Erik Lehnsher/Magneto (Ron Perlman) - the puzzle piece to reprogram the Sentinels
- Differences from the comics:
- In the comics, Carmen was enraged at Kitty's endangerment at Xavier. In the film, Carmen allowed Kitty to go with Xavier.
- Carmen's friendship with Charles and Logan is adapted from Excalibur Vol 3 14.
- Emma in the comics was never believed by Kitty to be her "Fairy Godmother".
- In the comics, Carmen was killed by Cassandra Nova's Sentinels. But in the film, Carmen's "death" was offscreen, and it was Sentinels by Bolivar Trask.
- Donald Pierce was replaced by Tom Cassidy.
- It is animated by Steven E. Gordon.