You are not the chosen undead

So I basically have this theory though it is probably wrong that the entire story isn't even for the character that we play as. My basis for this is that Oscar the very first npc we meet in the asylum tells us what seems to be the plot of the game how it was a story his family had passed down generation to generation and that becoming undead was considered a blessing. This makes me think that Oscar was meant to be the chosen undead but he ends up dying and we the player are fulfilling his last wish for him... any other ideas about this theory?

The title of "Chosen undead" was someone many people were after, so I don't think that Oscar saying that means anything other than what was said.

By default... anyone who completes the quest is the chosen undead!

I'd take it less as a destiny thing and more as a prophecy thing. If you manage to go through Sen's, get the Lord's Vessel, and defeat Gwyn, you are the chosen undead. If you can't, you are not. I feel that anyone who does those things is the chosen undead, so it isn't a birth right. It is a title earned.

All of those, "Soul of Undead," "Soul of Hero," and such, that you find are potentially the "Chosen Undead."