Logic

It's perfectly logical to add a character from Fandom A to a fic about Fandom B, right? Even though said character played a relatively minor role in the fandom and the character's fate is ambiguous as to whether or not said character survived, right?

Not even sure if I'm going to make this an actual crossover, or if I just want her there in the background. Though she may be called a Mary Sue if she knows even half of what she did in the original canon and people don't recognize her for who she is.