Greta is a person mentioned in the Dragons: Race to the Edge, Season 1 episode, "Crushing It"
Relationship with Gobber
Before the events of the How to Train Your Dragon Franchise, Greta was in a relationship with Gobber the Belch. What happened to end the relationship is unknown.
Greta's image is never shown in the Franchise, but Gobber describes her as a rather stout Viking woman. He names a defensive wall on Dragon's Edge, in honor of her strong, solid physical demeanor.
|| I'm going to call her Greta, after my first love. Large, sturdy. Beefy, some would say.
|| — Gobber in "Crushing It"