As from the Dictionary when used as a noun, "a nerd is a person who is extremely enthusiastic and knowledgeable about a particular subject, especially one of specialist or niche interest."
I can to some general extent consider myself a "Zelda Nerd". Overly enthusiastic towards the franchise, and fairly knowledgeable regarding it(there are some things I either have mixed up or don't know.
A "nerd" is often used to describe someone who has a strong and enthusiastic interest in intellectual pursuits, technical fields, or niche hobbies. Nerds are typically characterized by their deep knowledge and passion for subjects that may not be mainstream, such as science, technology, comics, video games, fantasy literature, and more. They often enjoy spending time on these activities and engaging in discussions about them.