Marvel Comics © October 1979, Fantastic Four #211.  The story is "If This Be Terrax".  Tyros becomes Galactus' new herald Terrax

Characters: Fantastic Four [Mr. Fantastic [Reed Richards]; Invisible Girl [Sue Storm Richards]; Human Torch [Johnny Storm]; The Thing [Ben Grimm]]; Herbie [Dr. Sun]; the Watcher; Terrax [Tyros] (introduction); Galactus; Silver Surfer (cameo flashback); Gabriel the Air Walker (cameo flashback); Firelord (cameo flashback)

Script: Marv Wolfman    Pencil: John Byrne, Joe Sinnott     Inks: Joe Sinnott