Kokomi Teruhashi in "The Disastrous Life of Saiki K" is portrayed as highly attractive and popular, often admired by her classmates. She is confident and sometimes appears vain due to the attention she receives. Despite her seemingly flawless exterior, Teruhashi is determined to get Saiki's attention, often leading to comical scenarios. She evolves over the series, showing deeper layers to her character beyond just her outward appearance and popularity.