Board Thread:Monster Discussions/@comment-25485523-20141203061800/@comment-26155014-20150424195151

ok let's see what we got here:

MechaGodzilla 1 was defeated by the regular showa godzilla even when he had an ally, so he will easily lose to them.

it would depend on which one, but King Ghidorah will probably defeat Gigan and Mechagodzilla since godzilla (in every time he appears except GMK) needed help against him by other monsters like Mothra and Anguirus or humans whom break the alien control over Ghidorah. Mechagodzilla and Gigan only "needed" Godzilla to be defeated (i know Gigan was killed by the final wars godzilla which is as strong as the heisei one but king Ghidorah is still stronger).

Kiryu could probably be defeated by Ghidorah or Destoroyah unless he uses his zero canon that will definitely destroy them.