Naki (亡 lit. "Death") was a System Engineer-Type Humagear and founding member of MetsubouJinrai.net who had possessed Isamu Fuwa to become Kamen Rider Vulcan (仮面ライダーバルカン, Kamen Raidā Barukan), and later became Kamen Rider Naki (仮面ライダー亡ナキ, Kamen Raidā Naki). They and their teammates later submitted to the Massbrain System and became Kamen Rider MetsubouJinrai (仮面ライダー滅亡迅雷, Kamen Raidā MetsubōJinrai).