What's been in my head lately is a Fantasy High pirate AU. Not a Leviathan AU, an actual pirate AU.
Adaine is a bookish princess of a kingdom by the sea, and while she has everything from an outsider's perspective, she's neglected by her parents as the second child and is incredibly lonely. Her only real friend is Kristen, who's a representative of the church of Helio and is kind of Adaine's unofficial lady-in-waiting, and both of them are fairly sheltered... until one fateful day, while the two are enjoying a small day of freedom, they get captured by a motley crew of pirates.
Fabian is the captain and the son of the fabled Old Bill, and he's been making his own mark on the seven seas via sheer charisma and chaos. He's trying to build up a reputation of being a ruthless thief and murderer like his father was, but it's pretty plain to see that he cares a lot more than he lets on... like, for instance, upon realizing that Adaine's parents don't care enough about her to pay for ransom, he immediately offers her a spot on his crew. And once Kristen has a very public crisis of faith, she's granted a spot, too.
The other members of Fabian's crew are as follows:
Riz, his first mate and best friend. He's a son of two prolific spies from the goblin kingdom, and he initially wanted to take down the vast network of pirates across the world, but quickly changed gears once he realized that working for the monarchy was a lot more morally corrupt. He kind of acts as the voice of reason, while simultaneously being one of the most feral members of the crew.
Ragh, the ship's chef and the other first mate---Fabian couldn't decide between him and Riz. His mom used to be a pretty prolific pirate herself, and he and Fabian have known each other since they were kids... and, yeah, their relationship has changed from "best friends forever" to "work husbands" over the years. They have some good times.
Gorgug, the ship's resident gunner. He grew up in a family of blacksmiths, couldn't find a lot of honest work, and eventually got a steady position on Fabian's ship. He's happy to be here, he's happy to show off the fact that he's a beast in combat situations, and he's one of the most technically savvy members of the crew. Also, he's a surprisingly good listener.
Fig, the musician and "dark sorceress" of the ship. She used to be a traveling singer-slash-songwriter and used an elven disguise to blend in, but eventually decided "fuck it" and took on her true form as a free-spirited tiefling pirate who kicks ass, takes names, and curses anybody who badmouths her. She's great.
Tracker, the ship's surgeon. She was raised in the church of Helio before being bitten by a werewolf, after which she promptly left to learn under her uncle, who was a prolific pirate himself before he retired. Nowadays, she's learned the secrets of both witchcraft and medicine and made a name for herself as a skilled healer and fighter, and is pretty happy where she is.
Gertie, the ship's other chef and resident wildlife expert. She's definitely one of the most friendly members of the crew, and even though she butts heads with Fabian a lot, she's a pretty core part of the crew. And yeah, between her and Tracker, Kristen is definitely getting a big lesbian awakening.
There is, of course, still a version of Leviathan out there, and Ayda still lives there as a librarian... which is the reason why the crew regularly makes stops there, though getting more supplies is also a plus. Garthy is also there, along with Sandralynn and Jawbone (and Hallariel and Gilear, much to Fabian's displeasure). The Seven are also around---they're a fierce crew of pirates who have a bit of a friendly rivalry with Fabian's crew, though it's never escalated into outright battle.