Thank you for answering the question on cinder but I am confused because the shadow fission is then breakable. I read on hisako's page that her 2 hit into shadow is unbreakable damage that leads to a combo. Why is it different for cinder because his shadow follow up is always breakable.
Hisako (and Orchid) have rekkas that are really... weird. They don't trigger the "this is a special move" until the 3rd hit, so you can do raw 2 hit rekka into shadow move and this is not breakable because the game thinks you haven't done a special move until the shadow move. On the other hand, if you do a normal canceled into 2 hits of rekka and then further canceled into a shadow move, THIS becomes breakable because of the 3-Move Rule (check my rewritten combo breaker page: http://ki.infil.net/cbreaker.html); the normal is your first move, "2 hits of rekka" is your second move, and the shadow is the 3rd move. The game still thinks you haven't done an opener or you haven't done a special move, but the 3-Move Rule catches this specific case.
I will go through my Hisako page and make sure that I make clear what is and isn't breakable about 2 hits of rekka into shadow move... it's possible I have some misinformation here.