Yuka's the classmate who dragged Yatora into the art club—basically the glue holding that friend group together. On the surface, they come across as this loud, confident type with a cutesy, over-the-top personality that naturally draws people in. But there's more going on beneath that brightness; they deal with real anxiety underneath the cheerful act.
Their grandmother is everything to them. She's the whole reason Yuka got into Japanese art in the first place, and they definitely put on their best face whenever she's around. When things get genuinely stressful though, that composed exterior cracks pretty fast—they tend to get brash and react impulsively rather than think things through. It's like their two modes are "bubbly performer" and "chaotic under pressure," with not much middle ground.
Content compiled by AnimeList.moe from publicly available sources.