Globally, Kasei (Kasei 
, Касей 
) is a common boy's forename. The given name Kasei is habitual in Japan, where it is quite a rare boy's name, Kyrgyzstan, where it is a rare unisex name, and Ethiopia, where it is a rare boy's name. Measured by absolute frequency, it is the most numerous in Japan, Ethiopia, and India. Also, Kasei is the last name as well as the forename.