The first set art some of the earliest designs done to find a mood or vibe to the character, something about a withered, depressed, and resigned vibe took hold. Then went forward with some designs with Raf's quicksculpt to the final concept incorporating Sinmara's heart!
Vance Kovacs https://www.artstation.com/americanbean and Karl Lindberg had some great explorations: https://www.artstation.com/artwork/6bKXNn