If we do get a season three, though, just being open and honest here, I really don't see Aeon, Guest (unless that guest is HUGE), Yun-seong, and either Rock or a new character, drawing in as many sales as Tira, 2B, Amy, and Cassandra or Hilde, Haohmaru, Setsuka, and Hwang. So that being true, it puts a possible damper on the likelihood of a season three being a certainty. SoulCalibur just unfortunately does not have the massive rosters that other fighting games have to pull DLC characters from, and they seem less inclined to make new characters as DLC, at least so far as they've shown.
But then, let's assume we do get a season three, would we then get a season four? I really don't think so. The effective pool of characters remaining at that point would be Li Long, Algol, and Dampierre, assuming we still have to have a guest, which is presumed true until they release a season pass that doesn't have a guest in it. And... yeah, Li Long, Algol, Dampierre are not really names that move sales. They have their fans, to be certain, but I can't imagine very much true hype being generated around that group of characters, unless there was another new character put in to replace one of those three.
And being completely generous that we do somehow get a season four, then a season five just becomes practically impossible, because there's just no one left, literally no characters left that aren't one-offs, the kids, or Z.W.E.I., and while we might could get Z.W.E.I., I have my personal doubts for the same reason that I don't believe we can see Viola in SoulCalibur VI, that their time is indeed for the future, in SoulCalibur VII, and not before. Amy is already confirmed to not turn into Viola as of 1590, so it would just be strange to have her ahead of schedule. And I don't see Z.W.E.I. working before then either.