10 Surprise Final Video Game Bosses That Came Out Of Nowhere
10. Calasmos - Dragon Quest XI
This one sits at the bottom of the list due to Calasmos TECHNICALLY showing up before the final battle, but in a side quest that almost everyone misses due to the game never telling you "oh by the way important plot stuff is happening at Galapolis maybe you should stop by". Of course, due to Dragon Quest's nature of being a celebration of tried and true JRPG tropes, it shouldn't be that surprising that you kick god in the teeth at the end.
Calasmos is an eldritch god of emptiness, born at the dawn of time who seeks to return everything to the nothingness that encompasses his being. Originally, the other big bad, Mordegon, stopped Calasmos from returning after he took over the world since it's kinda hard to rule the world when there is no world.
But then you go back in time and erase the entire second act of the game from ever happening, meaning that Calasmos is reborn unhindered. Oops.
And so the game's true final boss is this giant Cell-from-DBZ looking dude whom the hero has somehow less connection to than he did with Mordegon, making the whole thing feel utterly transparent.