Zero, nicknamed Big Guy, Kiddo, Ze, is a creative child known as a Sharkoi who wears his heart on a sleeve and believes in the good of others. He can technically have an idea on who is and isn't a bad person, but he needs confirmation by his adopted father, Spark. Zero is also kind, sweet-hearted, and loves to stargaze and create art. Even if he isn't fully talented yet. He was found one day after a horrible event so he's known Spark for almost a year since then, and has classed him as a father.

Zero has a childish voice, medium-range tone and can't really understand big words, but he can understand the simple sentences based on what they mean or relies on Spark to help explain. Anyone can audition, you just have to really channel that child voice. Tails from Sonic, Ben from Ben 10 (original series), and Gohan (child) from DBZ are good examples and inspirations to go off of.