Ursulas Return adds further versatility to the strategy in the shape of Diablo who lets you draw cards whenever your opponent does, as well as thanks to CriKee
But does it always have to be that way
If instead the creature you control is an illegal target but the creature you don't control is still a legal target, nothing will happen when Rabid Gnaw resolves
Unlike many other cEDH commanders, it isnt locked into a single win condition, so you have multiple paths to close games depending on the situation
Newer titles have moved away from the paradigm of the heroes of light collecting the scattered crystals in favor of broader, more convoluted plot-lines, but most games in the series still have a crystalline element somewhere
Magic: The Gathering has created a Standard-legal Universes Beyond set capturing the headliner entries in MTG form, along with a set of Commander decks to celebrate some of the more popular numbered titles