To clarify the link between Under the Black Moon and Off-season · 6:51pm Jul 28th, 2021
From the Off-season's point of view:
0. Both books should be okay to read without knowing the other part.
1. Under the Black Moon happened a few (unspecified, but really little. Less than twenty, likely less than ten) years ago.
2. World of UtBM, as presented, lay right there in Off-season, beyond the portal of Littlehorn. The portal is still experimental. The portal was built as a joint effort from both sides shortly after the end of UtBM. It works both ways.
3. World of Off-season is... pretty relevant to canon one, and most everything that happened in canon, happened there. You can place Off-season in a 'near future after Season 9' and you will not be wrong. There are many events that did not happen in canon, thanks to the major difference of AU, which is: notable 'gray-ing' of later seasons of MLP:FiM has an in-world cause: Off-season, which is to say, 'a night comes to town'. It's not an overthrow, and it's not even drastic or catastrophic. It's a cosmic seasons change.
Oh, and one more important thing to note: while time goes forward with the same speed for the both sides of the portal (it's NOT like in fairy tales, when a day there is a century here), timelines are shifted, and always were shifted. For Metropolis' citizens, step through the portal is like a step into a distant past, with a chance to view ancients with their own eyes.
