Usui is initially portrayed as a domineering and stern individual. He is highly intolerant and demanding, pushing Yako and Neuro away from the crime scene to ensure that the police department receives all the credit when solving cases. Usui also tends to boss Sasazuka around, largely due to a lingering grudge stemming from a past incident. Additionally, he dislikes Higuchi for his irresponsible and laid-back demeanor.
Despite these traits, Usui is fundamentally responsible and dependable. He holds great pride in the police force and demonstrates strong leadership skills, capable of inspiring the entire department with just a speech. Sicks recognizes Usui's capabilities, noting that while he isn't extraordinary, he stands out during crises. Following the Histerrier case, Usui becomes more amiable towards Yako and Neuro, beginning to trust them. He even funds Yako's food expenses during the HAL arc and follows Neuro's directions regarding Kasai's location.
In private, Usui has a fondness for cute items like stuffed animals and flowers, often blushing when such topics arise. He also enjoys sweet treats, getting irritated at Sasazuka for serving him black coffee without sugar. In an omake, the artist suggests that a Mini would be the ideal car for Usui.
(Source: Neuro Wikia)
