Yeah, that's how I've been riding the late beginning/early middle of Champion Game - pretty much on the fly. The thing I'm agonising over most now is how long I want it to be. I mean, I could make it go for the full year that Ren's Champion, which would take aaaaaages (like 1000 chapters ffs. Well, by the current rate, one year would take . . . *maths* 3405 chapters. Shoot.), or I could condense it into a fic that basically follows the plot far more closely. In that case, it would only go for maybe 120-180 chapters? Still heaps . . . depends on the reception I guess. My impulse is to go for the latter, have some form of conclusion be reached, and then fast forward to the following year's League Championships. At that stage, I'll see whether I want to continue it. If I do, he wins. If not, he is defeated and must step down. Of course, that still leaves room for a sequel, either with Ren or with the new Champion.
Yeah, one of the best things about the arts is just how much they evolve when you're doing them. Whether it's music, writing, drama or visual art, the end product almost never ends up the way you intended it. Even Champion Game is already vastly different to how I imagined it would be when I started.