Appearances by untransformed Kamen Rider characters in adaptations

A Friend in Need
In the opening scenes of  part 1, when Dex is talking to King Lexian while digging and working with the other Edenoites, the person wearing the breath mask is actually Kotaro Minami from the third episode of Kamen Rider Black RX. The rest of the characters in the scenes are Black RX characters, but Kotaro's eyes are visible through the mask.