Yuki is a 16-year-old high school student who's become one of the most popular JK streamers around. She's got a massive following on social media, though most people know her by her nickname, "Smile"—a play on her name, since Yuki can mean "happiness" in Japanese.
The thing is, Yuki's pretty self-conscious about her teeth, so she almost always wears a mask. It's become kind of her signature look at this point, which honestly just adds to her appeal for a lot of fans.
Content compiled by AnimeList.moe from publicly available sources.
