The False King other wise know as King Ghidorah is the most powerful of the villans. in Godzilla king of the monsters Ghidorah is awaken and fights with Godzilla at the end Godzilla kills Ghidorah and is then the king of the monsters . The False King is a alien form space and one miny theroy i have is if King Ghidorah is from space we dont know if hes the smallest of his kind or biggest or if hes just a test dummy that went to earth to see if its worth takeing

Scar King first appear in GxK or Godzilla X Kong and he proves him self as a big threat he . in GxK he holds any where from 10 to 50 apes in a lava hell scape.the apes move stones around the prison . and if the drop it they get attack or worse .as kong makes it to scar kings jail he sees decapitated apes on long wood spikes . he also see a ape drop hes stone and some other apes go and kick the ape that drop it on the ground then kong comes and helps up the ape that was kicked then scar king comes out and fights kong latter in the movie scar king makes it on land but so does kong godzilla and shimo they fight and shimo freezes scar king and kong wins

MechaGodzilla is one of the most known in the monster verse. In GvK Godzilla VS Kong is when he is seen Mecagodzilla was made out of one of King Ghdorahs skulls it was made by Monarch and was sopost to help humans fight kaiju but Ghdorah skull took over mecha godzilla and went to fight godzilla and mechagodzilla almost kills godzilla until kong came and help kill mechagodzilla