I used to be a part of this role-playing game (long story), but I was thinking kinda about RPs in general, here: you know what would be an awesome muse to RP? The Oxford English Dictionary. Think of how you could respond to prompts! To other characters whining about various things! You'd have to probably have an extensive vocabulary to begin with, but think of how it would grow! And you could use the sample sentences after each definition iteration to really tell a story or to communicate with other RP'ers. Oh my gosh, this idea makes me want to actually apply for the character, no joke.