The axe murderer
For I am death and I ride on a pale horse
Yeah that true by show. I think the ghidorah from godzilla earth anime is the most powerful. 20 km long, from another plane of existence, unkillable, Was a universal threatThis question's prolly better to ask by each individual series since the power levels vary from showa, heisei and millenium eras. But overall Destoroyah is #1, he was tanking attacks from Burning Godzilla which is stated to be the most powerful version of the G-Man (that awful anime doesn't count). For all his hype King Ghidorah was never close to killing Godzilla the way Hedorah, Mechagodzilla and a few others were on his own. The one time he was close he had help from Gigan
Hedorah is prolly the most powerful from the Showa series. Shot Godzilla's eye out, melted his hand down to the bone and nearly drowned/suffocated him. If Godzilla didn't get help from the military he was getting killed and Hedorah would've taken over the world.
Showa era Kumonga is a VERY underrated kaiju. No one brings him up because he's just a giant spider but Godzilla only escaped because he had help from his son. Only the combined atomic breaths of him and Minilla hurt Kumonga who's web was shown to be just as strong as Godzilla's beam. No to mention he stung Godzilla's eye out and poisoned him. Another kaiju that actually did more damage than King Ghidorah