|This article is about a/an kaijin in Kamen Rider Black RX.|
Skullma is a Grim Reaper-style monster with a scythe that was capable of flight and was assisted by two hornless versions of himself called Skullmastars. He played a part in Kohtaro's rebirth into Black RX. He was killed by Black RX when an explosion occurred in the water that Skullma and the Skullmastars were in. Following Skullma's death, the Skullmastars live on to serve the Crisis Empire on different occasions.
Skullma returned in the Kamen Rider: Run All Over the World movie to fight Kohtaro alongside the Skullmastars before he was sucked into a dimensional warp.