The final boss of may have deeper connections to an often forgotten villain. It's not uncommon for games to reuse big baddies — after all, how many times has Ganon been the final boss?
The series timeline tends to loop back in on itself, with much of the plot centered on the constant recurrence, throughout multiple millennia, of its heroes and villains.
It's no more a surprise to see someone like Ganon or Vaati in every subsequent game than it is to see Impa, Link, or Zelda herself. [Warning: This article contains major spoilers for the final boss of Echoes of Wisdom.] Even so, the recurring villain in history are relatively few.
By all appearances, has an original final boss, unused in any other game. However, look a bit deeper, and its villain has some serious similarities to another one-hit wonder boss.
The connections are never made explicit, but they're worth exploring to understand how ties into the wider lore. 's final boss, Null, shares a lot in common with 's Demise.