Hyrule Historia said it was a parrellell world of Hyrule.I am still very reluctant to believe that Termina is an alternate reality of Hyrule. I think that it is just some other land that is far away. But if it is, Link and the other triforce holders probably dont have a Termina counterpart.
The problem with this is that Link's actions were never forgotten, they simply never happened on that timeline. Link's efforts have, more or less, been remembered by generations after generations after generations [see: Twilight Princess and The Wind Waker]. Maybe not taken as they should've been, but definitely remembered.Darunia is a war hero who was murdered and his actions forgotten with time, much like Link's valiant efforts to save the Hyrule were forgotten after the defeat of Ganon (with "time," perhaps, in that he went back to before the events ever occurred).