In my opinion, the backstory and interaction between them is way more important than actually calling each other "brother" and "sister" every sentence Very happy to hear you tried your best to do this, will start a play-through soon. Very excited, because the lack of incest when the setting is perfect for it, was my biggest 'disappointment' with the game.I would say it alters the backstory rather than changing it completely. I tried to catch everything that doesn't make sense with them being siblings and hopefully I caught everything. Most of the files are changed with added reference to your new relationship and I tried to balance it so it's obvious you're siblings but not silly like calling each other brother and sister at the end of every sentence. I tried to have it so Cute calls you brother by default, but will use your name if you're doing something that annoys her. It's hard for me to judge how well I succeeded, hopefully I did decent. You can change what they call you in the settings cog as I know different people like different titles.