What was the name of Achilles' companion who was killed by Hector?

Achilles’ companion who was killed by Hector was Patroclus. In Homer’s Iliad, Patroclus enters battle wearing Achilles’ armor to rally the Greeks while Achilles remains withdrawn after his dispute with Agamemnon.

The disguise initially frightens the Trojans, but Patroclus overreaches. After killing the Lycian leader Sarpedon, he continues fighting near Troy’s walls. Apollo strikes him and helps strip away his protection; the Trojan warrior Euphorbus wounds him, and Hector delivers the fatal blow.

Patroclus’ death changes the course of the epic. Achilles is overcome with grief, ends his quarrel with the Greek army, and returns to battle specifically to avenge him. Achilles later kills Hector and dishonors his body before finally allowing Patroclus to receive funeral rites.

A common mix-up is treating Patroclus as Achilles’ brother or servant. The Iliad presents him as a close companion and fellow warrior; later Greek and modern traditions have interpreted their relationship in different ways.