There is no story. Just adventurer shipwrecked to island. There is main quest line to follow, completing main quests, map will open more. Now game world has spawn areas what spawn enemies. When player is level 60, then all those areas change and spawn only high level enemies. That way player can adventure everywhere, not just couple high level areas. When player is level 60, enemies start dropping end game stackable item and player got special repeatable quest. When collecting enough those items, badass boss will spawn. If boss is killed, then player got again that item collect quest and can do it again and again. On level 60 there are mini bosses too that spawn around world random places. So end game is just killing enemies and finding or crafting better loot. There is no "The End".