Born in Japan and raised abroad, Kosei spent his childhood and adolescence in Europe, primarily in Switzerland and the United Kingdom.

While living in the UK he worked to understand local culture and to share Japanese culture, and served as MC at a charity event hosted by the Japanese Embassy in the UK following the Great East Japan Earthquake.

After training in acting in the UK, he has continued his theatrical training in Japan, working across a broad range of acting techniques. He produced the short films "Brothers" and "Sayonara", and produces "Poach★Star", a video group themed around cross-cultural exchange.

His conviction is to bridge the gap between Japan and the world through the craft of communication that only entertainment can offer — encouraging others through an identity and concept that transcends fixed assumptions, and opening paths to growth and success in a spirit of mutual prosperity.