After the death of the dark Aethiopans' leader Memnon and the funeral of Antilochus, Deiphobus and Paris rallied the Trojans and poured out of the the city, only to be forced back by Achilles, who wanted to avenge both Antilochus and Patroclus. That battle would be the demise of Achilles, who Paris shot in his one vulnerable point, guided by Apollo.
After Philoctetes returned among the Argives and killed Paris during a duel, Helen was given in marriage to Deiphobus, but it was a joyless marriage for her. It was during the wedding ceremony that Eurypylus, the son of Telephus, king of Teuthrania, and grandson of Heracles, came to help Troy.
After the Argives seemingly fled, leaving behind them a wooden horse that the Trojans thought to be a gift to Athena (but was in fact hollow and full of warriors) and brought inside the walls of the city, the Trojans feasted until they fell into slumber. At that moment, the Achaeans opened the gates from inside, and their armies entered Troy. Despite Helen's demands that he would not go to the battle, as he was heavy with wine, Deiphobus prepared himself, only for Menelaus to enter their chamber, kill him and reclaim his wife.