Something based on the Yatagarasu novel series (also see the currently airing anime: Karasu wa Aruji wo Erabanai/The Raven Does Not Choose Its Master) with its incredibly interesting lore mixed with some gritty Game of Thrones court politics.

A couple of lore beats to whet your appetite on:

• People in this world are called ravens, where they can shapeshift between their human form and a large, three-legged raven form. Their third leg in this form allows them to shift back into their human selves.
  
  
• Ravens are separated in a caste system: from court ravens (adjacent to being a noble), to hill ravens (commoners), to "horses" (ravens subjected to remain in their raven form permanently and work as beasts of burden)
  
  
• The kingdom's ruler called the kin'u, or the 'golden raven' oversees four provincial lords, from North, South, East, and West, and these four noble houses compete for the throne's favour by sending brides to be wedded into the royal family.
  
  
• A lot of political nuances, from jealous princes with plans to usurp the throne, to the complicated dynamics of the caste system and how it affects the lowest members of society (i.e. one of the worst punishments shown so far in the anime is something called disarticulation: cutting off a raven's third leg while shapeshifted so they can never return to being human again, consequently working them as a horse for the rest of their life)