Which bastard son of Robert Baratheon was omitted from Game of Thrones?

The bastard son of Robert Baratheon omitted from Game of Thrones was Edric Storm.

Edric is Robert’s only acknowledged bastard in the novels. He was conceived when Robert seduced Delena Florent on the night of Stannis Baratheon’s wedding. Because Edric had royal blood, Stannis placed him under the guardianship of his brother Renly at Storm’s End.

After Renly’s death, Edric became important to Stannis and Melisandre. Melisandre claimed that his king’s blood could be used in a sacrifice to produce magical power. Davos Seaworth ultimately helped Edric escape to Lys, saving him from being burned. This storyline was replaced in the television series with Gendry, another of Robert’s bastards.

Gendry is therefore a common mix-up: he appears in both the books and the show, while Edric appears only in the novels. Mya Stone, another acknowledged bastard of Robert, was also omitted from the television adaptation.