So basically my theory is when i thought about what the worlds each were protecting.
Polaris has the sky anchor, which is matter, holding the sky and land together.
Mirage has the sands of time, which is obviously time.
My theory is that the next world, empyrea will deal with reality, since the bat is said to be able to shapeshift and master of illusions which in games can change reality in a way. My bet is that empyrea will have something dealing with reality.
Now the rest of my theory for hidden lands and broken shore.
At the end of test realm(*spoilers*) with mirage, grand spider has the key which is mellori. Now why would he need a "key", my answer to this is to find the hidden lands. Now at the end of mirage spider also said grandmother raven stole his heart, obviously hiding it. So the key is to find the hidden lands and find his heart.
My theory for broken shore is that its a term for the spiral when we fail to stop him from regaining his heart, he breaks apart the spiral therefore breaking it apart.
Second theory is that hidden lands and broken shores are just terms for other worlds.
