Who was the Trojan ally who wounded Diomedes with an arrow?

Pandarus was the Trojan ally who wounded Diomedes with an arrow.

Pandarus was a renowned archer from Zeleia, a city in the Troad, and fought on Troy's side. In Iliad Book 5, he shoots Diomedes during the Greek hero's devastating attack on the Trojan forces. The arrow pierces Diomedes' armor and wounds him, but Athena gives Diomedes the strength to continue fighting.

Pandarus then approaches with Aeneas, who serves as his charioteer, hoping to finish the wounded Greek. The plan fails. Diomedes kills Pandarus with a spear and seriously injures Aeneas, who is rescued by his mother Aphrodite. Pandarus' death marks the collapse of a Trojan attack that briefly seemed promising.

A frequent mix-up comes from Iliad Book 4, where Pandarus first becomes prominent by shooting and wounding Menelaus, breaking a truce between the Greeks and Trojans. He wounds both Menelaus and Diomedes, but the question's specific target is Diomedes. Paris also uses a bow elsewhere in Trojan War stories, but he is not the archer in this episode.