Board Thread:Versus Debates/@comment-43403813-20190907005521/@comment-31338621-20191003204724

It was definitely a substitute. If you look at the panel where Itachi starts running at Kabuto, he has part of Susanoo still over his head, so it had to have been the real Itachi.

If Itachi attacks Pain from behind, they won't see him.

Amaterasu didn't burn slow against The Rock toad, so it can burn faster if needed.