It's not clear if you have a full party yet. If you don't I'd like to pitch
Cargill, a hobgoblin defector from the Dominion.
A scrawny hobgoblin, small for his size compared to the attacking sailors, had been on board the attacking hobgoblin ships in the recent battle, and was found afloat out of uniform among the detritus of a sunken vessel. He claims to be opposed to the Dominion and what it stands for. Maybe he's technically a prisoner, or maybe he has even been enslaved, but Cargill wants to prove himself useful to those who have found him.
Honestly, it's more about the character than the mechanics. I see three obvious ways to build him, each of which would be distinct and (I hope) useful to the party. (Hobgob from Volo; each build uses something from SCAG that I've not played before).
1. Hobgoblin Cleric of Knowledge (or perhaps Arcana). Receives his spells from Maglubiyet, even though he (a) isn't evil, and (b) isn't a war priest. Claims he has been expelled from the Dominion because he preaches a kinder, gentler (and therefore heretical) Maglubiyet.
2. Hobgoblin Storm Sorcerer. Apprentice to the sunken ship's sorcerer, in training to be given his own ship; the strength of the Dominion fleet resides in having a sorcerer aboard each warship.
3. Hobgoblin Mastermind Rogue. The most servile of the three options, this build would be ingratiating and helpful, always keen to find a way to provide assistance while discreetly remaining in the background.
I'd be able to stat up any of these fairly quickly if chosen.
NPCs (great idea, by the way):
- friend: Tiroo. Happened to be chef on the ship that rescued him, and was there when he was pulled out; previously had held a position preparing food in a Dominion outpost; before that was peeling potatoes for a barracks that had housed his trireme's crew. It's amazing how diverse are food prep jobs he has had.
- contact: Madeira Franchthi-Wyn, former Olympian ambassador to the Dominion, now retired.
- foe: Hark Colpan, Hobgoblin bounty hunter seeking to recapture any who have fled the Dominion without authorization.
It looks like a fun game, and I'd be keen to join if there were room.