Endymion Whitethorn, aka Enda, is Rowan Whitethorn's cousin and a prince of House Whitethorn. After Rowan's own parents passed away, he grew up with Endymion.
Endymion, like Rowan, has silver hair. His eyes are green, flecked with brown that can swallow the colour when he is angered. Though muscular, Endymion is not as burly as Rowan
According to Rowan, Endymion is better suited to court machinations than the battlefield.
Endymion possesses a calm, wise demeanor, and he is willing to sacrifice his own happiness for what is right
As Fae, Endymion is able to shift into one animal form, that being a peregrine falcon. Endymion also has other natural Fae abilities, which are swift healing, increased strength and speed, and enhanced senses. As a member of House Whitethorn he can control ice and wind.
After the deaths of Rowan's parents - Endymion's uncle and aunt - Rowan moved in with Endymion and his parents. The two young males grew up together and formed a friendship. Eventually, they each began training in different skill sets.
Rowan claims that Endymion interfered with his business where he shouldn't have, but he later realizes that Endymion did so to protect him.
On the eve of the battle with Maeve's armada, a desperate Rowan decides to entreat his kin to betray Maeve and fight for Aelin instead. Endymion is the first person he visits. Endymion isn't startled when Rowan flies into his room in hawk from before shifting, instead remarking that his cousin looks different than he did the last time he saw him. Rowan reciprocate, and Endymion tells him that this is because of his mate. Rowan correctly guesses that Endymion's mate is Lord Kerrigan's son, and Endymion affirms, saying that they mated and married early that summer. Then Rowan explains to his cousin about Aelin and the threat that Maeve poses, and entreats him for aid. Endymion listens intently before saying that he will consider it.