Fog Mother
A cybernetic parasite from another galaxy comes to Earth with the intent of hatching millions of children which will feed on all living things on Earth, including humans.
Fog Mother lives inside a giant battle machine. She is physically attached to it so that damage to it wounds her.
Fog Mother's three oldest children, Agito, Garai, and Zoo, abduct a human child to feed to their siblings when they hatch. They also battle Kamen Rider J.
To Battle Kamen Rider J Agito, Zu and Garai revert to their true forms.
After her children have all been killed Fog Monster uses her battle machine to fight a giant sized Kamen Rider J.
