Asteropaeus was a leader of the Trojan allied Paeonians along with fellow warrior Pyraechmes. He was the son of Pelagon, who was the son of the river god Axios and the mortal woman Periboia daughter of Akessamenos.
Asteropaeous had the distinction in combat of being ambidextrous and would on occasion throw two spears at once. In the Iliad as the Trojans attacked the Achaean wall, he was a leader of the same group of the Lycian warriors with Sarpedon and Glaucus. It was this group which pressed hard enough to allow Hector and his troops to breach the wall.
Later during the siege Achilles is mercilessly slaughtering Trojan warriors alongside the river Scamander, and polluting the water with dead bodies, including one of Priam’s sons, Lycaon.
With the river god Scamander pondering how he might stop Achilles, Achilles in turn attacks Asteropaeous (himself the grandson of a river god) whom Scamander instills with courage to make a stand against Achilles.
Achilles and Asteropaeous engage in combat, Asteropaeous throwing two spears at the same time at Achilles. One spear hits Achilles’ shield, while the other hits the right forearm of Achilles and draws blood. Asteropaeous was the only Trojan in the Iliad who was able to draw blood from Achilles.
However he fails to kill Achilles and is slain.
Achilles is to boast that though Asteropaeous may be descended from a river god, that he, Achilles, is descended from a mightier god, Zeus. Later, in the funeral games for the slain Patroclus, the bronze and tin corslet, and the silver studded swords of Asteropaeous are awarded as prizes.