|Power Source||Atomic Energy|
|Pilot|| Limited AI
Dr. Hell (Remote Control)
A green humanoid demon-like Mechanical Beast wearing some sort of large blue mask that allows it to fly.
Abilities and EquipmentEdit
With the press of a button, Demos F3 is able to disassemble and reassemble itself. It contains three missile launchers in its skull. The blades on its head can be used for combat and when rotating allow the Demos to fly.
HistoryEditThe Beast is first seen ripping Koji Kabuto in half ending the pilot of Mazinger Z's life. The military tries to stop it but to no avail and they are all blown apart by the beast. This all turns out to be a simulation put out for Dr. Hell and Baron Ashura to show the capabilities of Demos F3. Dr. Hell then pushed a button which causes Demos to disassemble into pieces. Ashura is shocked by this and ask why Dr. Hell would do this. However Dr. Hell then pushed another button which recomposes Demos back into shape. Demos is next seen when Ashura shoots missiles on the foot of Mt. Fuji with the Saluud with the pieces of Demos inside of them. When the Photon Power Team investigate the pieces reassemble and attack the crew. Koji tries to lure it away while the others go back to get their mechs. Koji gets caught and is thrown away by Demos into Shiro. It then attacks the fleeing team with its beam. Attacking Boss' gang mercilessly it changed targets. It chases after the three doctors which Koji tried to protect only to be knocked unconscious by the beast.
Sayaka goes to Koji to reveal the Mazinger was launched only to see them defeated. Sayaka wakes Koji up about Mazinger and they both head off with Shiro following. Demos is assaulting the unmanned Mazinger barely being able to scratch it and Koji cannot approach less he gets attacked. Sayaka goes to get Aphrodite A hoping to stall the beast buying time for Koji to connect with Z. While Koji goes to get the Hover Pilder, Sayaka and Aphrodite fights with Demos with little effect. As Sayaka is forced out of Aphrodite, Koji arrives with the Pilder and manages to connect to Z. Mazinger and Demos proceed to brawl with Mazinger giving a brutal beatdown and using its photon beam. Mazinger finally beats it with its Breast Fire melting the Mechanical Beast into sludge.
- Demos is the first Mechanical Beast in the anime with the ability to fly.