Gus is a young and precocious witch. He is known for being very enthusiastic and excitable; when Luz gives him his nickname, he flips out in sheer joy. Due to being an illusionist, he tends to have a dramatic flair when making statements and presenting things.

He has a huge interest in researching human culture, also happening to be somewhat of an expert on it and was the president of the Human Appreciation Society at his school, even though his knowledge on humans is often inaccurate.