That is indeed a kid with a knife. A kid in a green sweater too, so Frisk isn’t really misguided to be nervous for a moment.

Still, when Yukio hears Frisk’s voice and turns around, he doesn’t look as comfortable with a knife as some would. He’s shaking just a bit, especially to see someone who told him that monsters… demons… were to be trusted.

“…Nothing. Just wanted something… just in case.”

His shirt is torn and covered with stains.