It may be the overall focus of Dark Souls from the perceptive of the player, but that is because the setting is with a very rich history and the events of the game are rolling along the momentum of actions that set it all in motion before the character you play as even existed. It is very much the situation of a being with divine power going up to every two bit schmuck that wants more in life and going "you are the chosen one" as the long con, figuring one of them has to succeed. Hence the cursed undead- hence the undead asylum.
The largest forces the player is exposed to as "major players" in the plot are those that covet the flame, never want the source of their power to be extinguished and will go to any length to keep it aflame, and those that are actively trying to use the power of raw darkness to undo the unnatural rekindling of the flame.
From my own perspective, it is the rekindling of the flame that is the true bad ending. Not just because of who supposedly got the last, smallest spark to give unto all of humanity and the hints relating to that, but also that those that seek to rekindle the flame are those that cling to the past where they were in power and drowned in luxury while doing to others what the dragons did to them and would burn the entire world- turn it all to ash if only to gain a moment more of their former glory. Those that seek their own flame are madmen seeking to become gods and damn the rest of the world in the process.
It is very much a situation lacking in any moral high ground. Everyone is acting on their own motives and most of those are in their own interests. True charity and selflessness is something lacking from the vast majority of characters that exist within the souls series and this is doubly true of those that proclaim their cause just and righteous.