Ukrainian soldiers Korean?

While watching the Ukraine War YouTube video, I was surprised to see someone wearing a Korean flag patch. Does anyone know who this is?

source:

https://www.youtube.com/embed/402hOvSZ7tA?playsinline=1&start&enablejsapi=1&origin=https%3A%2F%2Fwww.fmkorea.com&widgetid=1