Mach Achilles

Mach Achilles (マッハアキレス, Mahha Akiresu 9, 10, 21, 28, Movie) - An Achilles-themed turtle monster. At first he is able to block the X Kick attack and defeated Kamen Rider X with help from Apollo Geist by shooting him causing X to fall to bottom of the river. Later after Kamen Rider X has done his deadly training with Tachibana Tobei by shooting him with Machine Gun. He is able to defeat Mach Achilles with his new moves. He was destroyed by Apollo Geist after being defeated.

Apollo Geist's Last General Attack!!
Medusa have revived with other Kaijins, to support Apollo Geist, & defeated by Kamen Rider X again.

Five Riders vs. King Dark
Mach Achilles have revived once again with other GOD Cyborgs, to attack all over Tokyo and, in the middle of the crisis. & they were defeated by Five Kamen Riders.