So I've noticed writing on all the capes ever since I crafted the Shepherd's Watch, but I never thought much of it. But after crafting the Well-Engineered Ensemble (for which, by the way, I absolutely love the artwork) I decided to take a closer look at the writing to see if I could make heads or tails of what it was saying. At first, I thought it might be paleo-Hebrew, but upon taking a closer look at the latest cape, I noticed that it had a double letter, which is somewhat rare in Hebrew. So I decided to apply a logical English phrase: "Wonderfully Made" from Psalm 139. Sure enough, it fit. From there, I was able to piece together the other two, and here's the results:
With these three phrases, I was able to fill more than 2/3 of the English alphabet in this code. (The letter E seems to have two different designs) Some are similar or identical to English letters, while others are completely different.
If more capes get released (which I really hope that they aren't a Season 1 one-shot) it is likely that the gaps will continue to be filled in. And it makes me wonder if we'll see this "Aethasian Code" elsewhere in the game, or if it's exclusive to these capes.