The Rumors Are True!

[Kazuya]

Why can't they interact? I could see that coming into play if someone had two high-powered characters and wanted to use them to bum-rush the competition in sagas, but I don't see why they shouldn't be allowed to interact whatsoever. I'm just curious as to what the potential issue would be if a really bored and antisocial writer chose to use his two characters to spearhead a singular storyline.

^This. I think that stipulations that they are not to interact is a bit over the edge, maybe that they can't be used to gain an advantage would be a bit better.