This is a setting I’ve longed for since the first time I’ve heard of the concept of parallel dimensions.
I love time travel and alternate history, and they can meet in the concept of parallel dimensions.
I envision the multiverse as a d20 with each of the sides being one of the realities.
Each reality could have access to it’s 3 “neighboring” sides (the sides on each of the 3 sides of its triangle) and the opposite side (on a die: one and twenty, two and nineteen, and so on). Only the opposite side will be relevant in the first “season”/Campaign
Players would play as members of a secret unit of Interpol, the section X, which is tasked with resolving “paranormal” cases. Other such units exists internationally (as division of the FBI, FSB, or any state police organisation you fancy), but I’ve decided to play in Europe, hence the choice of Europol.
Main plot would be a cold war between our reality (Earth Prime, as we call it) and Earth Second, a slightly more technologically advanced reflection of our reality, where 9/11 happened differently and Covid-19 never left China.
I’ve decided to create a set of rules for this, mainly based on 5E and some grafts from other systems, like usage dice.
Here the Work in Progress of the character sheet: