There were Vikings with dark skin, including the twins Geirmund and Hamund, who were nicknamed Heljarskinn, which means "Black-Skinned". The Black Viking is also the name of a book by Bergsveinn Birgisson: a saga about early settlers on Iceland. It combines academic historical and philological scrutiny with personal notes and joyful storytelling. Research suggests that the image of Vikings as blond is inaccurate. Many Vikings had brown hair and had genetics from outside Scandinavia. 🤷

As an Icelander I disagree with you. It's a fictional story about dragons, it's not meant to be historically accurate.