This is probably going to be so AU it wont even be funny. All I know of this world is what I've gather from the movies and when I watched X-Men: Evolution when I was 12.
How will it be AU? The end of First Class is void. Or parts of it. Ok, just the part where Charles became wheel-chair bound.
Bare with me, and if/when I make some unforgivable mistake please point it out.
So without further delay, this is the prologue. The actual story probably won't pick up until the chapter after next.
Her appearance in their lives was unexpected.
Coming off of the feeling of betrayal and abandonment, the group was wary of new blood. Especially her's. They were so alike. Some held the hope that she would fill the void that he had left, others avoided attachment in the fear that they were too similar and she would leave in the same fashion as him; leaving them in vulnerable shock, at the most inconvenient time, in the most hurtful of ways.
The similarities were uncanny. Especially due to how soon she came after he left. It was almost as if he had walked out, gone on holiday, and returned as a whole new person after the whole ordeal.
However alike the two seemed, though, they were completely different where it counted. Where he was cruel, she was patient. Where he was full of hate, she was full of understanding and apprehensive hope.