Shadow Islet
Welcome to Shadow Islet!
Shadow Islet is one of the many Ethereal Islets residing in the Mirror Timeline. It is smaller than an Island, having 13 base monsters instead of 15. It may be unlocked by purchasing it for 
300,000 Shards, or by teleporting a level 14 
Pentumbra from Ethereal Workshop. This requires 
2,621,120 Treats.
Islet Mechanics/Getting stared 
Shadow Islet works quite different compared to Ethereal Workshop, or any standard breeding island. Unlike most islands where you work your way up to the quad, on the Islets you work your way down! Upon opening Shadow Islet you will be met with a Pentumbra ready to place. To start this Islet, you must click on the Dish-Harmonizer to squish the Pentumbra. Upon being squished, Pentumbra's elements will seperate back into meeb form, and the meebs will be added to your counter on the right. (You will have an infinite number of 
Shadow Meebs). These meebs can then be recombined into new monsters!The higher level monsters you squish, the more meebs you get, and the longer it takes to dish. When Dish-Harmonization is complete, your Pentumbra will have seperated into two other monsters. Sometimes the meebs recombine back into a Pentumbra, and sometimes they add new monsters to your collection!
Dish wishing 
Dishing is the same on all islets, so this is just an example. Once you've obtained 1 single, double, triple, and quad element monster on any islet, you will unlock Dish Wishing. What is Wishing? Wishing allows you to select monsters you want to get, and the Dish-Harmonizer will attempt to make these for an additional shard cost.
The circles will fill up over time when dishing, only if you get a monster with the same element count youre wishing for. For example, lets say im wishing for a blarret. I dish like normal, but I manage to get a 3 element monster that is not blarret. That is when the circle will fill up some, but not all the way. When the circle fills up to 100%, you will be guaranteed the monster you wished for! Note, just because the wishes say 87% for example, does NOT mean you have a 87% chance of getting that monster.
The Primordial 
Once you've dished for quite awhile, you should eventually reach the point where you have all ethereals unlocked on the islet. However, there is one special monster waiting at the very end.. and thats Fandhul!! Fandhul is the Primordial of Shadow Islet, hosting the Primordial Cold element. As for what a Primordial is, you may see in game descriptions. But how do we obtain a Primordial? More dishing! Upon unlocking all ethereals in the collection book (of one rarity), a new wish counter will be added to your dish wishing for free. It will have (), and will work the exact same way normal dish wishing does. Except, it will only go up when you get a quad in the Dish-Harmonizer. However, in order to successfully obtain a Primordial, you must have at least 3 of each element available in the Dish-Harmonizer. A 4 element monster may transform into a Primordial once these conditions are met.
Rares 
Rare monsters on any of the Islets are only obtainable by dishing regularly with the Rarefied Dish-Harmonizer. This upgrade will cost you 100,000 Shards. When Dish-Harmonizing, the monster you get will have a chance of turning into a rare! Well, if its available in the market. You can dish other rare monsters you get for a higher chance of getting more rares.
Farming
Farming on the islets is a very lengthy process, but very worth it if you're smart about it. Every islet has very different grid shapes, all not identical in the slightest. So, we cannot use the base island grid here. The following grid would be an optimal Shadow Islet setup that holds 81 monsters, and supports the full song while having 3 extra 3x3s.
- These grids are visible here
Alternatively, you may use this grid which holds 80 monsters while supporting the full collection.
- These grids are visible here
The best monster to farm on Shadow Islet is 
X'rt, as it is the highest 2x2 shard producer. It is also good to spam any other triple. Any of these triples may be replaced with their Rare variants, but there are no Rare Primordials as of now. So they will not be as efficient YET.