Board Thread:Theories and Speculation/@comment-36512555-20200202084241/@comment-9782468-20200212131628

@Flatzone again, the fact that it's a fire-breathing toad means absolutely nothing because Amaterasu burns anything regardless of what it is. Jiraiya used it to negate Itachi's Fire Release advantage, but he never saw Amaterasu before.

I don't like or dislike it. It's called putting the feat in context of the series. Sasuke is a better user of Amaterasu than Itachi ever was. Since Amaterasu never exhibited fast burning effects, there's a logical reason why the much weaker (by chakra strength and volume) Itachi made that happen. And there's your reason.

@Ninja I think Itachi made the first opening with Amaterasu and then him or Kisame or both blew it open from that opening