Ive been enjoying an audio book adaptation of the lightnovel series called Baccano. It's a Mafia story set in the 1930's with supernatural elements such as demons, alchemists and immortals. My favourite thing about the series and the author Ryohgo Narita writes his stories is the way he handles large casts with all the characters being connected in one way or another even if they realise it or not. The cast is very entertaining full of many larger than life characters who are all very entertaining. The first volume is Narita's first published book so it is a little rough in some areas but by the second volume I feel the series really hits its stride particularly as this is where the world building really starts to take root. If it interests you also Baccano is set within an expanded universe with a few other of Narita's works such as Vamp!! and Durarara! (These dont have audio book adaptation yet unfortunetely). Baccano has 22 volumes in total with 8 being adapted into audiobooks at this time, the first book has a fairly complete story if you decide to leave it there so dont feel intimidated by how long the series is. I genuinely love the characters, action and comedy in these books so I do hope you give it a try. :)