Genre-shifting traditional RPG settings

I’d like to take the rule mechanics for 4th edition D&D and modify the setting for a sense of variety. Since I can’t pretend to understand all of the intricacies of the system’s rule mechanics, I want to make sure that this modification is cosmetic only. This maintains compatibility with future errata, modules and expansions.

It’s a relatively simple exercise: take the setting (medieval fantasy) and adapt its fiction to another (say, post-apocalyptic cyberpunk). With our example we need to build a history from the modern world to the new setting’s context, although this isn’t always necessary; Sometimes a setting is just a setting.

Take the modern world as it exists today, but let’s assume two technological advancements are made: humans begin successfully genetically modifying themselves and Google researchers give birth to the first sentient AI. These two assumptions lead to a whole host of delicious setting elements.

• With the advent of genetic modifications, some humans would begin modifying themselves, while others would be wholly against the notion. Much like fashion subcultures exist today, the same might occur for genetic modifications. There’d be some areas of factionalism, maybe smaller pockets of cosmopolitanism. What we end up with here is our distinct races, languages, and cultures.
• Let’s say that the AI researchers spawned several instances of their successful prototype in an effort to recreate their success. Chaos would dictate that they’d grow distinct over time, maybe even begin fighting. With the rapid pace, maybe they changed the face of the earth in a span of four days. They constructed nanobots, launched themselves into backup copies in high-altitude orbit, maybe tried to nuke each other’s earthly servers. Our end goal here is to replace the original setting’s deities.

After that initial technological burst and the AIs nuking most of the planet, our setting decays for some unknown number of decades with dwindling natural resources, factions trying to rebuild some kind of security. We’re effectively set. It’s not that this setting is novel, but it effectively adapts the core elements of D&D into post-post-apocalyptic cyberpunk.

Everything follows from there. Diving magic used to rely on deities, now it relies on AIs exterting their dwindling energies on dispersed nanites. Arcane magic is replaced with advanced human technologies.

It’s not a perfect mapping, but it works. There are some side-effects to this. Clerics and Paladins (or whatever you’d rename them) are ideologically opposed to anyone who holds a grudge against the AIs. Of course, you could argue that this tension should exist even in the original setting. Point being, the specifics can be modified as necessary to accommodate the setting change. As the rules are never changed, we maintain game balance and everyone can still enjoy themselves.