That is (potentially) Sthalmann, a main character of the Version 1 Limsa Lominsa introduction; Commodore and right-hand man of the former admiral who, in 1562, led a coup against him (leading to said admiral's death) in an attempt to steal the pieces of a staff not unlike Louisoix's (though he could not make it function) so he could prepare Limsa (as he saw fit) for some great trial to come. Y'shtola caught up with his plot, but an Ascian made off with the broken staff piece (the horn) before she could recover it. After that, he lost his position and wandered the city a drunken pirate (captain of a crew of one), obsessed with his redemption, but loathed by everyone. His points of view weren't exactly right, but he wasn't quite as wrong as others turned out to be, either. As of 1572, he never quite got anywhere with it, but he was a well fleshed out and very interesting character, which made it more likely we'd see him again one day... that and the fact that Fernehalwes was also a fan of his, lol.