My partner and I saw this jam and was interested in the focus of the roguelike. We're wondering if there's gonna be a theme revealed once the game starts :0 does anyone know

I don’t think there will be any theme. You are free to make the game you want, given it respects the constraints listed on the page, to make it rogueliky enough.

all the requirements and direction is on this page https://itch.io/jam/roguetemples-fortnight

the good news is that you can pretty much use any theme as long as you design the game within the confines of a traditional roguelike 

yup, the theme is "roguelike" as per tradition :)