Additional Cast from the pic above:
Pri Pri Prisoner: Masaya Onosaka
Superalloy Darkshine: Satoshi Hino
Engine Knight: Yōji Ueda
Metal Knight: Tesshō Genda
Watchdog-man: Ueda Yuji
Lightspeed Flash: Kōsuke Toriumi
Pig God: Namikawa Daisuke
Atomic Samurai: Kenjiro Tsuda
Metal Bat: Wataru Hatano
EDIT: i forgot
Child emperor: Takayama Minami
Additional Staff:
Composer: Makoto Miyazaki