According to the South Korean news Agency, “the chief of North Korea’s military was executed this month on corruption and other charges, a source familiar with North Korean affairs said Wednesday. Army Gen. Ri Yong-gil, chief of the General Staff of the Korean People’s Army, also faced charges of pursuing personal gains.” His predecessors (Kim Kyok-sik, Hyon Yong-chol) were probably also executed.
I consider that he may have defect to a foreign country as did former executives of the North Korean Army. Some of them are based in the US. Ri Yong-gil was the chief of the General Staff of the Korean People’s Armywas the since september 2013.

Ri Yong-gil was probably replaced by Ri Yong-mu, an advisor to Kim Jong-il on military affairs and a former Director of the KPA General Staff Operations Bureau. I already predicted in the past, that Ri Myong-su will continue to maintain a high position in the North Korean leadership. According to a North Korean Source, Ri Myong-su used to be a military mentor of Kim Jong-un and Kim Yo-jong.