@TokenOtaku That's not what I meant. This isn't the world of the game, it's the world of the story of the game(kinda). The decisions of the players outside of the story-line have no relation to the decisions of the characters they role-played as. The characters of the Seven Heroes in the story of the game rebelled against the Tyranny of the character Ruphas, for the sake of freedom and stuff like that. In the published written lore, it wasn't because of a reason like "they wanted to fight so they did".
Plus, it's already been mentioned that the heroes in this world have had their own lives and motivations beyond the actions described in the story of the game. Ruphas' laws against discrimination of non-white winged Flugels being one of those things. The two heroes we've met so far also weren't players and had their own motivations(which weren't exactly those of the players, since for the players it was just a game). The memory of Ruphas drinking with them in a bar with the talking about their dreams was also shown as an example of an event that hadn't happened in the game, but did in the past of this world.
At most, you could liken the players' motivations and decisions regarding the Ruphas vs Seven Heroes war to the will of the Goddess in this world. However, while the motivations are the same, the difference is that unlike for the game, in this world it's the Goddess who willed it as part of her scenario rather than it being the will of the Seven Heroes.
(Here I mean that the Seven Heroes in this world didn't want the war for the same reason as the players, with the players' reasons aligning more with those of the Goddess, that is to say for the conflicts to continue since a complete victory and then no real conflict afterward was thought of as boring by the players. That's literally the reason why the players planned out that war, as said in the first chapter of the manga and novel. She had conquered all territories possible to conquer and no other players could thus start wars since they didn't have any territory left for themselves, and there was a need to have a kingdom to start a war against another. So they came up with the rebellion plan/scenario so to split the territories afterward and let the other players be able to do their own territorial wars.)
Now, speculation time.
The Demon King said that Ruphas was the only one able to move outside of the scenario of the Goddess. This in turns means that the Seven Heroes couldn't do that. The Demon King then also puts in question the decisions of the Seven Heroes 200 years prior as weird and out of character for them. Both of those ideas combined bring us to another possibility. One in which the Seven Heroes might have been manipulated(in one way or another) into rebelling against Ruphas prior to them all fighting together against the demonkind and the Demon King.
The question still remains how they were manipulated(or mislead, etc), and the "scenario of the Goddess" itself is still a mysterious thing in how it works...
To conclude, I personally think that it's not so much that the characters in this world wouldn't exist without the players having created them(since that would be putting too much power into the hands of the players in my opinion), but more so that in this world the Goddess and her scenario fill up a similar role to that which the players and writers of the game did back on Earth. I see it more so as a coincidence of a real world that just happens to be very similar to one in a game. (and if we go that way, then it's possible if basing ourselves on the theories of infinite possibilities of universes and parallel realities) That way, the real Ruphas is her own person rather than just a character created by a player in another world(Earth), the Goddess is the one responsible for the "scenario", and the characters weren't created by players but rather just people who were born in this world, grew in it and have their own motivations and have done things that aren't known to players who played the equivalent of that world as a game back on Earth.