Barnsy! wrote:First of all was we meant to know that the final boss fight takes place under Hyrule Castle? Because I didn't until I was told, haha - but it's kind of obvious once you are told
I don't think it's supposed to be certain straight away, but you can
jump down there at any time and find out. I had a peek quite early because
Zelda says you're in the foundations of Hyrule Castle in the game's opening, so I was like,
shouldn't I look for her down there first?. But if you don't, I think it's the
Yiga quest that tells you (is that right?), so you can get told what's going on a fair way before the end depending on the order you do things.
Barnsy! wrote:...final fight...
I'm not sure where you're getting the idea the final fight in TOTK doesn't change...! If you don't do the sage side-quests, that cutscene where
the sages show up and repel the boss monsters (where they say something like
"we've beat them before, we can do it again!") doesn't play and instead you have to
fight all the bosses one after the other, which is similar to how you
fight the blights before Ganon in BOTW.