This will be where the main plot takes you, as Griselda, in Chapter 3.
Calahree sends ol' Grizzy to figure out how to get to the Fairy Realm, as their queens Titania and Mab are responsible for guarding one of the crystals containing her essence.
The Maze is located outside the Eerie Cave, accessed via a new spell. Basically, it's a puzzle (kind of) where you need to get the right ingredients to throw into the lake.
The Fairy Realm is, obv, full of fairies and sprites. Those same little fucks you fight in chapter 2 as Ginny. But they're peaceful NPCs this time around, so no big!
And the temple is Queen Mab and Titania's home, where the Corruption of Calahree's Crystal has been well at work for the past few hundred years or so...
But more on that later!