This character is an NPC.
As is tradition within Toraigh, the menfolk disperse from their clans in pursuit of their calling. Often they return to their natal pack after some time away with stories to share, often with family in tow. The same could be said for Luithiarn. He was tasked with this same quest. He left Toraigh to seek out his hearth spirit (a guiding force, similar to a spirit guide, rooted in mythology). There are many gods within Toraigh and they are specific to each person, but oftentimes they lead people away from home for their own entertainment.
Luithiarn did meet many people and see many things, but through it all he pined for home. When he met Antiope Nereides he was struck by how abrasive she was, as most women were charmed by him in some way and she was revolted. So began the game of winning her heart; it was made more difficult because of the nature of Antiope's people. They were zealots in their own right, but more dangerous for Luithiarn was the prospect of being forced in to servitude, which Antiope warned against. They were soon swept up in the danger of it all and had their tryst, at which point the siren forced the man to leave before they could be caught together.
Luithiarn is one of the many children of Sithmaithe and Kyran of Toraigh. Through Kyran he is connected to his uncles Riordan, Murtagh, and Tiarnan as well as an aunt named Maura. Through his mother he is connected to his uncle Bairrionn and aunt Brid. They are a very old family with Celtic inspiration.