He Remains Unbeaten in the Field: The Song of Achilles/The Trojan War AU
Robb Stark is the son of a great Northern King and a sea goddess. Raised in his father’s court, he was groomed from a young age to be a strong and just soldier, loyal to his kingdom, kind to his friends, and brave when he faced his enemies. Because King Eddard Stark had a habit of bringing home wayward boys--orphans, exiles, and wards--Robb grew up with a band of close-knit friends he considered brothers, including Jon Snow and Theon Greyjoy.
When Helen of Sparta was kidnapped, the Trojan War began, and despite Catelyn Stark’s efforts to keep her oldest son far away from the violence, Robb knew his duty and set out for Troy, quickly gaining a reputation as a boy who could not be killed, who had never lost a battle--gaining as many enemies for his skill as he did friends.
Quick Summary: In this AU, Robb takes the role of Achilles--an impulsive, spoiled little prince with a big heart, too young and naive and too ready to believe in the best of human nature to realize he could be betrayed.