In Homer's Iliad, Lycaon is a son of Priam by Laothoe, daughter of the Lelegian king Altes — half-brother of Hector. Achilles captures him cutting fig shoots in Priam's orchard, sells him to Lemnos, and later slays him without pity at the Scamander during the aristeia after Patroclus' death. Distinct from Lycaon the Arcadian king (lycaon) and from Lycaon father of Pandarus.
Adapted from Wikipedia, "Lycaon (son of Priam)" · CC BY-SA 4.0
I.Son of Priam
Apollodorus and Homer place Lycaon among Priam's many sons; his mother Laothoe makes him half-brother, not full brother, to Hector and Paris. He lends Paris his cuirass before the duel with Menelaus, and Apollo once takes Lycaon's shape to speak to Aeneas.
While cutting wild-fig branches in his father's orchard by night, he is seized by Achilles, sold to Euneus of Lemnos, ransomed via Imbros, and restored to Troy — only twelve days before he meets Achilles again.
II.Death at the river
In Iliad 21, during Achilles' slaughter by the Scamander, Lycaon clasps the hero's knees and begs for ransom or mercy in memory of Patroclus' gentleness. Achilles, wild with grief, refuses and kills him, casting the body into the river.
The atlas id lycaon-trojan keeps this Trojan prince apart from the Arcadian Lycaon who serves human flesh to Zeus and from other Lycaones in the epic.