"Duke of the Isles?" What isles are we talking about? There are various isles in or near Eorzea (Sharlayan is an island city-state, for example), but none that would be controlled by a duke.
If you want to play an Ishgardian noble, your choices are vicount or baron. There are also counts in Ishgard, but only four of them, and we already know who they are. The higher real-world French ranks of marquis and duke don't exist in Ishgard, or anywhere else in Eorzea, seemingly.
Note also that Ishgard is the only city-state we know of that has a true nobility. Gridania seems to have a class of important people who get their own little part of the city to live in (I refer to them as the gentry for lack of a better term), but the city is governed by the Seedseers. Ul'dah is a sultanate, but the wealthy and powerful people there are the monetarists. Limsa Lominsa is led by an Admiral, so the closest thing to a noble class there would be naval officers, I suspect.
If you're playing a character from a made-up, faraway land on some other continent, then I suppose you could hold onto the duke and marquis titles, although some RPers might raise their eyebrows at you. I suggest you name his homeland something other than "the Isles" though, because again, what isles? And if your character is from a land far away from Eorzea, it doesn't make much sense that your character would know Eorzean beast tribe languages, especially if his appearance in Eorzea has been "rather sudden." Most Eorzeans don't even know beast tribe languages, because why would they? Beastmen are considered subhuman by most Eorzeans. And note also that we don't have any idea whether these tribes even have written languages.
I would study up on the lore a little bit and ask some questions to flesh out your character, if I were you. I think you can make your general character concept work, but if you're going to RP in the gray areas of the lore, it's helpful to be very familiar with it first.
Edit: I did some thinking after concluding this post, and it occurred to me from your character concept and the style in which you introduced it that you're going with an almost regency romance kind of vibe for your character. That can work, but it does have to be adapted to the game's lore. I did something similar with Solenne, who is a wealthy Gridanian aristocrat. She has many of the accomplishments and life experiences that a regency romance heroine would have, but she is also shaped by the fantasy-based environment of FFXIV.
If you want to play an Ishgardian noble, your choices are vicount or baron. There are also counts in Ishgard, but only four of them, and we already know who they are. The higher real-world French ranks of marquis and duke don't exist in Ishgard, or anywhere else in Eorzea, seemingly.
Note also that Ishgard is the only city-state we know of that has a true nobility. Gridania seems to have a class of important people who get their own little part of the city to live in (I refer to them as the gentry for lack of a better term), but the city is governed by the Seedseers. Ul'dah is a sultanate, but the wealthy and powerful people there are the monetarists. Limsa Lominsa is led by an Admiral, so the closest thing to a noble class there would be naval officers, I suspect.
If you're playing a character from a made-up, faraway land on some other continent, then I suppose you could hold onto the duke and marquis titles, although some RPers might raise their eyebrows at you. I suggest you name his homeland something other than "the Isles" though, because again, what isles? And if your character is from a land far away from Eorzea, it doesn't make much sense that your character would know Eorzean beast tribe languages, especially if his appearance in Eorzea has been "rather sudden." Most Eorzeans don't even know beast tribe languages, because why would they? Beastmen are considered subhuman by most Eorzeans. And note also that we don't have any idea whether these tribes even have written languages.
I would study up on the lore a little bit and ask some questions to flesh out your character, if I were you. I think you can make your general character concept work, but if you're going to RP in the gray areas of the lore, it's helpful to be very familiar with it first.
Edit: I did some thinking after concluding this post, and it occurred to me from your character concept and the style in which you introduced it that you're going with an almost regency romance kind of vibe for your character. That can work, but it does have to be adapted to the game's lore. I did something similar with Solenne, who is a wealthy Gridanian aristocrat. She has many of the accomplishments and life experiences that a regency romance heroine would have, but she is also shaped by the fantasy-based environment of FFXIV.
Michaux Vidal - Oyuna Qestir - Tatsu Kaisuri
Arnvi Sunblade - Noriyasu Kuroda - Lucien Lemaire - Bren'li Arhys
(See Tumblr for Character Profiles)
