Nightcrawler

This is one of the coolest mutants of the x-men, he's blue and he's crazy.
Nightcrawlers actual name is Kurt Wagner and of course he didn't have any of his powers at the time, but he still had his blue appearance. He was found half-dead on the side of a street by his foster mother Margali Szardos, who turned out to be a sorceress and gypsy queen. His alleged father, Eric Wagner and mother where found a short distance away from him dead.
Later on in his life it was proven that his mother was none other than Raven Darkholme, aka Mystique, and his father was the warlord Azael. Mystique through Kurt into a river because a crowd had found out about him. He was saved by his father and given to the Margali, a lover of his fathers. Wagner was raised at the circus where his foster mother worked and was treated like a normal individual there despite his appearance.
He had a large amount of natural talent for acrobatics, and since his body was shaped in a way that he would be perfect he became the shows star acrobat. The people of the crowds loved him and assumed he was just a normal human in an acrobatic costume.
The circus came under new owner ship and the new owner hated Kurt, so he made him part of the circus' freak show where he was drugged in order to prevent escape. He escaped by the help of another mutant and went looking for his foster-brother who had gone insane. Kurt accidentally killed his foster brother while trying to stop his insane rage and was chased by a mob that blamed him for the recent killings of many children and women. Charles Xavier, leader of the X-men saved Kurt's life and asked him to join the X-men.
Kurt discovered that he had the ability to teleport. He practiced with his ability, and figured out that the larger distance he teleported the more tired he became and that he had to have a clear view of the spot he wanted to teleport in mind or he might end up teleporting inside a solid object and injuring or killing himself. When he teleported it left a small bang of air rushing into the rip that he had just created. With more and more practice he found out out that the teleporting drained less and less out of him.
Nightcrawler is an extremely religious man and a devout Catholic. Since he has blue colored skin that makes it really hard to attend masses without freaking everyone out. The x-men designed a tool that created a hologram that made him look like an actual normal human and he wears it when he attends church services. He wanted to become a priest but was denied a number of times.
Nightcrawler had two best friends in the mutant world, Kitty Pride, whom he used to date and Peter, also known as Colossus. Peter came out to Kurt in one of the later episodes and Kurt being uncomfortable with him being gay left for a time, but then returned and accepted him.