Merriam-Webster says the first occurrence of "anybody" is in the fourteenth century.
I was thinking more in terms of when it came into commonplace usage: I have an OED looming behind me which has lots of etymology (actually quite interesting during a bored moment) but which seemed unwilling to commit itself in this case beyond "formerly".
Like I know anything about writing decent English anyway: I only studied it until I was 15.
And are those Persuasion checks even worth a damn or they are just fight not fight scenarios?
Seems to me like persuasion is shit.
Some of them are kind of important-ish, depending. The one that was a particular source of frustration was halting an execution. After assorted attempts to use different characters and attribute-boosting potions I eventually gave up with the diplomacy route and just attacked them instead.
