in the comics I think she was his mother. or they thought she was his mother or something. <sarcasm>cause they're both blue. so obviously they must be related. </sarcasm>
Yeah..no she was definetly his mother. ANd he was in some way related to that anti-mutant guy. And because Mystique was like Rogue's adoptive mother in disguise (she was the one that made her gain super strength and flying abilities) Rogue and Nightcrawler were like half brother and sister