I started creating this game almost 2 years ago and I spent most of my time on the plot. It turned out to be very difficult to create scenes if you don't know what will happen next. Thus, I already know exactly what will happen and at what point and how it will end. I hope this will help save time on development in the future.
By the time I stopped, it turned out that more than 100 characters are involved in this mess, and most likely this number will increase even more. It is true that almost all of them will have several endings of their own. But it is also true that not all of them have a super deep history. The supporting characters are also important.
This is such a double-edged sword that I wonder if early-ish comment could change your mind.
Knowing what's ahead and pretty much having the whole game already somewhat planned out can be good that it definitely saves you time for writing, but it can also be bad because you might have problem making adjustment to actually improve the game.
Less is more is never more relevant than this kind of situation. You said it yourself, "more than 100 characters are involved in this
mess" and I really want to emphasize that even your choice of word already acknowledge that it is a mess. This is not to say that your game is bad, but it shows that you're aware that the game is very very very big. You have to ask yourself:
1. "Do I really need ALL 100+ characters?"
2. "How long would I realistically need to finish this game if I stick with 100+ characters?"
3. "Would people continue to play/pay if they know it's THAT long?"
And finally, "How do I create a game that is equally good in quality but with significantly less number of characters so that the game can be completed in reasonable time, and that people will stay playing/paying without feeling bored between updates?"
All the best, mate.