The X-Men have faced impossible odds before, but things have never felt as dangerous for the mutant heroes as they do in Fall of X. The collapse of Krakoa has left the team largely on the run, with few advantages to speak of. But perhaps one of their greatest current assets is their spy within their enemies' ranks, who's currently subverting a trope of the modern era.
Source：https://www.cbr.com/xmen-traitor-firestar-colossus-beast-marvel-comics/
