Dempa Micomsoft was the software division of publishing company Dempa Shimbunsha. In 1993, it was broken off as a separate company, though fully owned by Dempa.
Apart from programming games, with Dempa earning a high reputation for its arcade conversions, it also made joysticks and other hardware. The company now remains as Micomsoft Co., Ltd., with TV scan converters as its main business.
Dempa Shinbunsha literally means "Radio Wave Newspaper Publisher Company", which is how they are listed in Generation MSX's developer register.