The Premise of our game is that of an academy for mutants to learn control, and to find new prospects for the X-men. Since our game doesn't follow any specific canon of comics, movies, or cartoons, there is a lot of freedom in character creation. We don't allow children of X-men (a la Rachel Summers), aliens (the Shi'ar), and the family trees may need to be edited (The Mystique family tree, for instance).
While we don't allow origional characters, but by allowing players to pull from different types of material, we are offering a lot of freedom on character creation. Almost any power set has been used in the comics, so with help you can often find a character to expand upon. (You really don't need to create a brand new pyrokinetic when there is Pyro, Flambe, Watchfire, Firefall, Brushfire (the last four having no real histories at all) to choose from?) We allow freedom with histories, so those characters that appear in one or two comics only are really up for grabs in terms of your ability to create a history and personality of your choosing. There are many background characters to choose from and we're more than happy to help.
There also is the possibility of taking a character that is well known, and adjusting them to our setting. A perfect example is Longshot
who has been taken from a interdimensional character with a history that would never be accepted (Mojoverse, really?) and put into a 'real world' setting. An excellent example of a melding of the the movie, comics, and cartoons is Rogue
Do remember that these are high school students. While we all have our favorite characters, it is impossible to have Jubilee have the entire history you find in the Wikipedia article. Also, please write the history or powers with a bit of your own flair. A copy/pasted Wikipedia article doesn't really give the sense that you even care about the character you intend to play. A good example of a character with a rich history that is condensed and alterted to fit our game is Pyro
If you have any questions, or need any help, please feel free to contact any of the admin. We can sometimes be found in chat, otherwise message Xavier, Dazzler, or Forge for the quickest response.