The other dimension, what is it?

Yeah so you enter Elin Forest from Ludi for that reason, right? since it mentioned "Broken Gate of Time" so I guess it was part of the Time Sphere malfunctioning which accidently opened the gate to the past?

Anyway, other dimension. What further explination you want about it? the title explains it self, there is basically another dimension out there.

there's practically nothing known of what's going on with Elin since there's no quests and the NPCs don't speak in game.