Marwyn Storm is an unseen character in Game of Thrones. He is the only named bastard son of Lord Rickard Harrigon.
Marwyn was born near Smithestone and was brought to his fathers home when he was four years old. Lady Lorra Wendwater doesn't think anything of Marwyn, as she knew all of the previous lords of Hornworth fathered countless bastard children.
He began his training as a blacksmith in Smithestone at the age of eight, and is being instructed by his uncle Rolphar Storm