I'll be nominating Vampyr! Like the title suggests, it's about vampires in 1800s England. In addition to the protagonist there are lots of side characters to choose from and prominent het and slash options.

There are a few Let's Plays but the game has lots of side quests and optional stories, so if you don't have access to the game itself you might be better off with the cutscene compilation:

https://www.youtube.com/watch?v=5lb5cmlHids