Well imo, a franchise killer is a game that definitively pulls the plug on a series. Like the Dragon Quarter example I mentioned - the fanbase was already split on IV, but then when DQ came about, it was so unpopular while taking up enough resources that Capcom decided it was no longer financially viable to continue the series. Whatever your thoughts on FFXV are, it was still popular enough (at least with the new crowd) that the FF brand is still very much alive and kicking. XVI might very well kill it though, but it’s still not the time for that.