(first of all, no, in my version, Monster X and Kaizer Ghidorah are seperate monsters. Monster X didn't transform into the ghidorah, but rather fought through the story as himself.)
height: 120 to 200 meters
weight: 40,000 to 500,000 tons.
Xaliens. A lawless bacteria-like race known to take the bodies of those who steps into their planet, Mars. Able to manage to took over one body during one of the failed martian landing on 1960, the xalien later calls himself "X" and began to construct his empire. using their vast intellect on machines, they create enough ships, weaponries and cyborg bodies to conquer the planet filled with their much needed bodies: Earth.
After a failed conquest during 2009, X gave up on Earth after finding another race that could support their bodies, the equally technologically advanced Venusians.
By 2014, the venusians seek help on our planet. Seeing that his new target had taken refuge on Earth, X captures some of Earth's monsters (namely Ebirah, Gorosaurus for a short while,Ganimes, Titanosaurus, a first generation Zilla, Kumonga, Kumacuras and Maguma.) and implanted control collars on them to command them unto attacking the Earth Globally. Fighting back, Earth's Defense Force (EDF) used their's and the Venusian's technology and warfare against them. At the same time, some of the remaining monsters began to fight back as well (Kamoebas, Manda, Anguirus, Rodan, the venusian's Jet Jaguar, Mothra, Varan, Baragon, Gorosaurus after being freed from the xaliens and Godzilla.)
As the war came down between the EDF battlecraft Gotengo and the xalien mother ship, X went down on a mental breakdown after seeing most of his fleet fails (save for his two cyborgs Gigan and Megalon) he injects himself with a serum made from a Godzilla cell sample he once acquired. Soon, he began to mutate and murder his own fleet, thus resulting into the birth of Monster X.
As Godzilla, Jet Jaguar and the Gotengo battles Gigan and Megalon, Monster X arrives to even out the odds. But who will win? ...
~ can levitate himself and fly at a short distance
~ can fire gravity beams from his "eyes"
~ can fire a spiral- gravity flare from his mouth
~ capable of doing martial arts (since he is once humanoid)
~can drain energy at will
~ appears to be capable of communicating with his "creations" Gigan and Megalon
~ can fire gravity spheres from his palm
~strength of a monster's ten-fold
~ can grow stronger by the energy he absorbs
weakness (spoiler!) :
~ though he can absorb and use energies that are used against him, he appears to have a limit to this ability; anymore beyond his limit may severly injure himself or even killed him. (but he was not aware of this...)
story (c) mine