Miu is described as an oddball, having an overly confident, loud personality and a frighteningly sharp tongue. She considers herself a beautiful genius, and every time she opens her mouth she spews a parade of reckless vulgar remarks and insults, strongly putting pressure on others and looking down on them. In the original Japanese, she even uses the Japanese word "ore-sama" to refer herself, which is considered very arrogant and more traditionally masculine. She also tends to give other characters insulting nicknames.

Voice reference: https://www.youtube.com/watch?v=ImOCymgLyB0&t=263s