Huh? He's from Generation X.
https://marvel.fandom.com/wiki/Natha...er_(Earth-616)
You're probably thinking of Morph, who got his codename on Generation X but did debut in Bendis's run.
https://marvel.fandom.com/wiki/Benja...ds_(Earth-616)
Silhouette has no association with the X-Men though. She's actually appeared since the Krakoa era started... in Ironheart.