Crows also tie back to the "Underworld" series of movies:

"The Corvinus Clan has been around since at least the early seasons of the fifth century, if not earlier. Described by Lycan scientist Singe as "the rarest of bloodlines", it was from within the blood of one Alexander Corvinus, a Warlord, Duke, and the Patriarch of the Corvinus Clan, (and a recipient of this same rare bloodline), that the Corvinus Strain was mutated, in his immune system's response to a plague that ravaged his home village, his rare bloodstrain bonding with and adapting the plague virus, and himself in turn, to his benefit. In the end, Alexander alone survives the plague, becoming "the first true Immortal"."

Vampires could be code for users of adrenochrome.

"According to the documentary Fang VS. Fiction, there was a real life Corvinus Clan around the same time as Vlad the Impaler, and that there were stories circulating about members of the clan becoming Vampires and Werewolves, as well as other things. According to history, the most memorable head figure of the real life Corvinus Clan was Matei Corvin/Matthias Corvinus (King of Hungary)."

https://underworld.fandom.com/wiki/Corvinus_Clan

They also tie in with Great Britain and the Tower of London:

"Brân the Blessed, the mythical king of Britain, is represented by crows and ravens in Welsh mythology. In fact, the name of the king itself means “crow” or “raven”. According to a folklore in the famous Welsh Triads, the king’s severed head was buried on the location where the Tower of London stands today. It was believed that as long as the head remained there, Britain would never be invaded by an outside force. King Arthur, however, is known to have dug up the head, in order to affirm his power and strength in the kingdom. Nevertheless, even today, ravens are looked upon as protective spirits, and the birds are looked after at the Tower of London, under the care of a trained Ravenmaster."

https://mysticurious.com/what-do-crows-ravens-symbolize

This could come into play should the Monarchy fall:

"The Ravens of the Tower of London are a group of at least six captive ravens resident at the Tower of London. Their presence is traditionally believed to protect The Crown and the Tower; a superstition holds that "if the Tower of London ravens are lost or fly away, the Crown will fall and Britain with it."

Later legends

"It was said that at the execution of Anne Boleyn in 1536, "Even the ravens of the Tower sat silent and immovable on the battlements and gazed eerily at the strange scene. A Queen about to die!" The ravens of the Tower behaved much worse during the execution of Lady Jane Grey in 1554, purportedly "pecking the eyes from the severed head" of the queen."

https://en.wikipedia.org/wiki/Ravens_of_the_Tower_of_London