The Miraculous Valley's Princess (奇跡の谷の姫君 Kiseki no Tani no Himegimi) is the sixteenth episode of Kamen Rider Black RX. It introduces Joe the Haze following his appearance in the previous episode. It's the third part of a four episode story arc. It also features the debut of Roboizer, the first of two alternate forms for Acrobatter accompanying those of RX. In this case, it corresponds to the Robo Rider transformation which debuted in the previous episode.