Clearly quests and story lets you go on adventure to fight big badddies then you get to end and fighting big baddie which is long time dead before you even starting fight with him , yup makes so much sense.
And saying you can do it 2nd or 5000Th million time lol what a nonsense.

If i go 2nd time same happends will you go and tell me go it 3rd time LOL. if you think that makes any sense then you are lost and clearly have no clue how story flow works and how it makes sense.