The thing about ants (and usually insect species in general) isn't that they're individually strong unless they're of the atlas/stag beetle family; it's more that there's way more of them than there are of you, and you will run out of stamina before they run out of reinforcements.
His child is literally half spider, whose birth he missed because he had to deliver an Asura-style beatdown onto a god of darkness. Nothing is standard, here.
I don't think it's the actual Amaterasu (though that is not out of the cards), I think it's some up-jumped spirit co-opting her name in no small part due to her being a mother of other deities (as well as a mother of monsters). It may even be Susano-o stirring shit in her name, because her...
If she hadn't already had the impulse and urge, the Goddess wouldn't have been able to influence her. The onus is still on her. Raul said as such when he was punishing the would-be rapist suitors way back when. All the goddess did was remove her restraint, the original ideas were still...