It was no secret that Emma and Erik hated each other. Emma had worked with Sebastian Shaw, the Nazi madman who had killed Erik's mother and mercilessly tormented him in Auschwitz. Erik didn't blame Azazel, Riptide, or Angel for siding with him. They didn't know who Shaw had been. In the time Erik had known her, he had never told Angel what Shaw had put him through. When Erik confronted Azazel and Riptide, neither had known the truth about Shaw's past. Azazel had known Shaw had ties with the Nazi regime, but he never knew exactly what Shaw had done. Both were horrified when when Erik revealed the truth to him. They had worked on Shaw's side long enough to know he could be cruel, but the extent of his cruelty, to a fellow mutant no less, was appalling to them. Erik still had difficulty trusting them, but he couldn't fault them for something they had no knowledge of.
Emma was different. Emma had known. She was a telepath, and a pretty powerful one at that. There was no way Shaw could have hidden his past from her. He hadn't even tried. Emma had known exactly what Shaw had done to Erik as a boy, and she worked with him anyway. Despite Erik conceding that what Shaw had done had made him stronger and that he agreed with Shaw's beliefs that mutants were the future, he still hated that madman with a fiery passion. The fact that Shaw had supported Adolf Hitler's cruel regime was reason enough for that. Erik had always figured that if he could have controlled his ability to manipulate metal, he would have found a way to use it to stop the Nazis. Shaw had known how to use his ability, but instead of trying to stop the Nazis, he had sided with them. That was unforgivable in Erik's mind. But Shaw was dead. Erik had made sure of that himself. He couldn't hate Shaw forever (though his heart would try). There was no use in it now.
But what about the woman who had known all of that and loyally fought by Shaw's side? She had known the details of Shaw's cruelty and still remained true to him. Not only that, but she had displayed affection for the man. If her relationship with Shaw had been strictly business, Erik could have found a way to work with her, even if he couldn't be friendly to her. But she had loved Sebastian Shaw even while fully knowing what he had done while he was calling himself Klaus Schmidt. The thought of Emma's love for Shaw made Erik sick. He didn't like the idea of working with her. But all of his plans worked only with a telepath.
Having spent so much time with Charles had that effect on Erik. Oh how Erik wished he could still work side by side with his only true friend. Charles had unlocked such strength in him. And not just with his powers. By simply being Erik's friend and showing him that he could trust someone, Charles had helped Erik grow stronger. If only Charles could see his point of view. He always hoped that someday he and Charles would work together. Then he would have his brother back. Then he would have no purpose for Emma. He could get rid of her, one way or another. He had no particular desire to kill a fellow mutant. He feared that sooner or later the humans would take care of that. He had seen humans hating what they don't understand come to fruition before. He wouldn't wish that fate on anyone, not even a foe like Emma. That didn't mean he wanted to work with her though. He sometimes considered breaking his rule of not killing a fellow mutant to deal with her. But he knew he couldn't. She was too valuable a pawn.
