Frill was designed by Acca and Ura-Acca to feature traits a father would want to see in their daughter. Frill is cheerful and clever by design, showing intelligence significantly higher than that of the average fourteen year old. She also has a sense of humour, and is often seen laughing as a result of practical jokes or general silliness. Acca and Ura-Acca intentionally designed her to have flaws as well, giving her the capacity to express certain negative emotions, such as selfishness. 